Bf keeps asking for anal

My bf is pretty persistent in asking me if he can put it in my butt.

Now we have tried this like 4 or 5 times so I know it’s not something I really enjoy. No matter how much lube, no matter how slow he goes and i don’t like the feeling that I’m gonna poop lol.

However there was one time that it happened and I was drunk and he had told me that it looked like I really enjoyed it, but I mean I was drunk I don’t think I felt any sort of pain. Which is probably the reason why he’s persistent.

Yesterday he had asked once again and I said no. I forgot how the conversation really went but I do remember asking him “so even if it’s not something I like or want to do I’m supposed to let you do it” and his answer was “yes, cause it’s my penis”

I just gave him like the WTF look and he didn’t say anything he just continued on his phone.

At times he gets a little upset over it and at times it makes me feel like I’m the bad guy cause I say no. So I guess my question is should I just let him do it to please him or should I stick my ground.