I WANNA LEARN HOW TO TAKE THE D

Lately it seems like when I have sex I feel it so much in my stomach. My guy isn't even that big. He's a nice decent size but I feel it so much in my stomach. It doesn't hurt but it's not the most pleasurable. It's been a while since I've had sex but I don't remember feeling like this before. Only if the guy was really big or he was doing it from the back or something. ..I used to really be able to take dick tho lol. So I'm not sure what's going on. What might be the issue ? How can I get back to soul snacthing and feeling comfy with the d in me