Poking!!??

So when my boyfriend & I have sex sometimes I'll be laying on my stomach & he'll stick it in sometimes it goes so far in it I feel like I can't take it or it hurts not even sure if it hurts? Like its poking something? When I ride him sometimes it pokes something & I don't know what it is but I can't keep doing it so I change positions?? Another time is when my hands are on the wall & I'm bent over he gets so in there I feel like it's hitting something & my entire body reacts to it & needs to stop? I'm not even sure if I described that in a way anyone could help me but if anyone can please help!😅