First time A*** s**. Use plenty of lubricant – Petroleum Jelly is best because any tears,it helps heal them from inside and take it slow. For you to be fucked, it will feel like a s*** going the wrong way up your b*** hole and it might hurt a bit to begin with, but once your a****** is stretched open, it can become pleasurable, especially if you play with yourself, while you are being b*** fucked and having him c** in your tummy could be quite a turn on.
One of my girlfriends said “this is not right” after I came in her tum, but it felt great to me and once she got used to it, she wanted it whenever I did, which was most of the time……….Best wishes