Being My Brother-in-law's Substitute Luna

　　Mary's POV

　　Helping my twin sister has always been my priority right from when we were kids. What she asked me to do recently is what I'm still wondering, if I can opt in or not.

　　Lucy, being married to the Alpha Prince second-in-line of succession, Prince George is quite bound by some rules pretending to the royal family. She can't attend unsolicited events, coupled with the fact that she has a baby son whom she takes care of with her husband. Prince George doesn't need a maid, so she has no choice but to take care of her son by herself.

　　Last night she called me, informing me of a friend's birthday party she wanted to attend. I can remember furrowing my eyes while listening to her, even though we were on call.

　　"Are you sure this event is quite suitable for you?" I asked her about the rules anyone in the royal family of San Marino had to follow. This was from what she had been telling me and from what I heard on the television.

　　"No, it's not permitted, of course you know but I want you to sneak into my house late in the evening before my husband comes back from work. Just pretend to be me. You will return in the morning before he wakes up, I'll be back by then."

　　"Oh my goodness!"

　　"No panic, no worry," she rushed over her speech. "You know how identical we are in appearance, the color of the eyes, voice, and hair. He wouldn't detect it."

　　"I'll tell him tonight I just want a day off without being touched by him, a day off breastfeeding our baby directly, I'll use a feeding bottle with my squeezed breast milk instead. Any conditions appropriate for your stay with him, I'll do it."

　　"Hmm," I swallowed the saliva in my throat.

　　"It's alright but is this party important?" One mind was dragging me from going in for this risky task while another was urging me to help her as I'd always helped. But still, I wanted to know how important this party she wanted to attend was.

　　Prince George is the one sponsoring my studies and my master's program in college. He is likewise the one taking care of me in general being his mate's sister and I know he's doing this because he and my sister are together. Anything I'd do to make them still together, I'll know all there is to lose if they should separate. Aside from this, I love my sister so much. Even though I'm still single, I'm happy having a sister like her, who's a princess by marriage. This would make me opt in for this task, even if I'd never do it.

　　"My best friend in high school and college is celebrating their first birthday after moving to San Marino. The one who helped me push up with my grades and as well saw me all through the difficult times."

　　"Well, that sounds like a justifiable excuse." This is how it sounded in my ear, especially her last statement. "Okay, I'll do it!"

　　This person was good to her and she can at least repay him by celebrating with him. She has been telling me of this wonderful person each time she recounts her life in high school. We happened to gain admission into different schools.

　　"Wow, wow! Thanks so much, Mary, for coming in through for me, you're such a darling!" I could hear her blowing several kisses on me over the phone, I could even hear her jumping around. I wondered if her husband wasn't around, so I couldn't afford to ask.

　　"No, he's always back from work at 7 PM nowadays." He is working as a senior doctor at the Royal Medical Center, close to the palace, which isn't so far from the private apartment they live in outside.

　　"Oh, that's nice." I'll memorize everything in my mind, including the likely conversations that might kickstart while with him and how to respond.

　　"Till tomorrow!" I say at last before ending the call. I get in for a little pride since I will be the one to help her. I know Lucy, she will smile at this.

　　Seeing the most eligible bachelor sitting here right in front of me in my white net maternity gown with my bra and pants see-through made my hormones high. Louis, the five-month-old son of my elder sister is breastfed through his bottle in my hands, I'm shaking right inside of me but I try my best to compose myself.

　　This man is fucking charming!

　　Just as his position says.

　　"Oh God, don't let me be exposed!" I pray inside of me, my heart is beating so hard right now. Something whispers into my ear, "You're his mate for the night, behave as one."

　　I take a deep breath. Then look right up at him. His radiant blue eyes shine over me with lust. I want to question him but then I recall after all I act as his mate.

　　"Have you forgotten about what I told you yesterday?" I slightly frown my face to know that I'm serious. He grins so quietly, in a sinister mood which is interpreted to mean he wouldn't be sticking to what was agreed on.

　　"I'm the Prince, my mate can't be detected when I'm to touch her and when not to. I'm horny, either fuck me tonight or I go out there and fuck. I'm a man, so I know how intense it can be. I have many girls out there at my disposal, just that I choose to be faithful to you."

　　My mouth becomes mute. I can't react to what he just said. I know it's nothing but the truth. I have no defense.

　　"Why punish me for no just cause, are you sick?" He leans to ask me and I shake my head.

　　"Should I go out there and find someone more romantic than you, you right know what will happen to our marriage." His tone was sarcastic here, but I know he can be tempted to do it.

　　I narrow my eyes, thinking about this again quietly. "Is he really serious with what he's saying right now?" I ask myself.

　　"Who wants to take chances?" A voice was speaking through me, and I shuddered. "Remember you are Lucy right now, he sees you as his mate. Refusing will give him a second thought. Why don't you accept it?"

　　My mind is working up a lot of thinking at this moment. "Why me? Why must this happen?" My eyes turn dull and my head turns. I came here to represent my sister, you act like she's the one, being that I know about almost everything that happens in their life being sort of a counselor to her as a caring twin sis, I wasn't too scared of coming here although I was initially.

　　Prince George's asking me for sex now is the serious challenge I'll be encountering. I don't want to cheat on my sister with her husband, one thing that made her tell me yesterday she doesn't want him to touch her today knowing fully well she wouldn't be the one present.

　　"Are you in for this or not?" The prince asks, his voice both stern and gentle at the same time, a dangerous combination. I swallow the lump in my throat. When I didn't say anything, he asked further.

　　"You don't feel like having me touch you, have I failed to be your husband today?"

　　"I... I....don't worry." I pushed forward to him so his hands could reach me. This marriage is special to my sister and me as well. I know the great things George has done for me as a sister-in-law. Aside from this, having a sister who is married to the prince is something to cherish and protect. I didn't want my own decision to crash her marriage, she might never find someone like him again and I'd be lost, I'd go bankrupt, I'll have no one to take care of me.

　　His hands pulled forth in front of me, caressing my soft boobs as I was in Lucy's lace bra. I raise my head, trying not to enjoy, not to fall for the sensation that's climbing up my body. He squeezes me hard, then slides his hand inside my right boob, nibbling at my nipple. My core is pulsing right at this moment.

　　I watch as he pauses all of a sudden, taking the baby away from me, and going over to his cradle to lay it to sleep. Then he returns to the bed, sitting right in front of me, he pulls up his T-shirt and then his boxers, setting eyes on his huge cock which was already aroused because of me makes me shut my eyes briefly.

　　"I'll be taking you to cloud nine, my charming, sweet mate!" He extends his hands right across to carry me up.

　　No! No! What if Lucy returns to know we had sex, wouldn't she see me as a traitor? Or is there something I can do right at this moment to avoid it?