Im having trouble getting deep PIV with a new sex partner. I get huge pleasure from PIV so I’m eager to get it right. I’m chubby with a big butt, he’s more skinny with a noticeably thick, average length penis, for reference? We’re a few inches apart in height.

I know the head of the penis is getting in because he comes from the sensation of being inside and I feel it, but it doesn’t go deep. This doesn’t make sense to me because only a bit shorter in length than others I’ve been with with no issue, so I don’t feel like we should have penetration issues. But it keeps slipping out. Or I have to hold my body in one perfect spot and can’t move even slightly or he’ll slip out.

I feel like the only position that works perfectly is me lying on my back with my legs spread open and very wide. Reverse cowgirl was perfectly deep too but I wanted clit stimulation. Regular cowgirl, my arm isn’t long enough to reach around my butt and insert the penis. So far from behind, didn’t feel deep.

Part of my wonders if maybe it slips out because I’m tight- I know I’m smaller than I used to be, from some meds I took.

I’m so confused why this is happening and how to like fix it! How can I play with position to get it to work?

Edit: not interested in comments suggesting he or I change who we are, but feedback from folks experienced with this issue who have position based tips are welcome.