If your partner cums inside, it kinda feels like you have to take a runny shit. If your partner cums a lot, it can make you feel like you have diarrhea. However, cleaning well afterwards is key. I use an enema before and after if my partner cums inside. For a first timer, it will feel like you have to take a big shit, even after you're done having sex. The rectal cavity will get a little swollen from having foreign movement going on inside. This is why it feels like you're constipated or have to poop. After a while and doing it enough, your body gets used to it and the sensation is less intense. Hard pounding will also jostle your intestines. This can give some people a tummy ache. And lastly, pulling out completely and thrusting back in will force air into the rectal cavity and doing that a lot will push air into the intestines, causing a gassy or bloated feeling. Ripping a few big farts usually makes it go away. LOL
Anal is not for the faint of heart or people who get embarrassed over farts and feces. It's painful and causes a lot of embarrassing noises and situations (feces on the penis, farting during sex, etc). If you love your partner enough to let them into your backdoor or enter their backdoor, then you love them enough to overlook things as trivial and expected as farts and feces.
My first time was an "illegal lane change" (doing it doggy style and it slipped out of one orifice and into another abruptly). It hurt so bad that I turned on the spot and punched the guy in the face. He fell backwards off the bed and hit his head on the wall! So, yeah. It's painful for both top and bottom. LOL It's definitely an acquired taste. I happen to really like pain, so it works for me, but it's not for everyone. Still, I'm glad I could help.
Does anyone else wonder if cumming in a booty hole will make your stomach hurt in real life or is that just me? Everytime i read a Yaoi there like don't cum in my ass my stomach will hurt.