I think I might be able to help but everyones body is different. So I dont think its a problem of you being tight. Most hemroids develop due to straining when you have a bowl movement. So unless you are really bearing down when you are bottoming I think its an issue of how you are cleaning your hole before you head out to fuck.
I had a hookup one time and I didnt have a lot of time to prepare and be clean. I grabbed my bulb enema and started to prepare like I always do, but this time I was trying to get all the water out quickly because I didnt have much time. He came over and we had amazing sex and he was cute as fuck .... After he left I noticed an itching sensation, so I grabbed a mirror to check it out. And there it was a fucking hemorrhoid, I was really pissed because no one wants to eat out hemroided out ass. Anyway I went to my Doc and explained what happened and he told me what I am telling you.
1. If your going to use an enema avoid the sensation to push the water out as fast as you can, just let it slowly flow out.
2. When you have a bowl movement never push down hard, your body will naturally expel your dodo, obviously you are going to push a little but take it easy.. So grab your phone and watch some porn, find a new hookup or whatever and take your time.
3. Diet.... A healthy diet is key and fiber is your friend. Most of us bottom boys have a good diet, thats why I think it a preparation problem.
4. This next one my doc didnt tell me but this is what I do: I always use a good toilet paper and make sure I am all cleaned up. The trick is you dont want to wipe to much because it causes other problems. So I just do a general quick wipe and then I use a moistened wipe to clean up the rest. You can use the Charmin pre-moistend wipe but I dont like it because it is scented and that irritates my hole.. So I you Preperation-H wipes. It has witch hazel in it which is a natural astringent that wont irritate your bum.
I hope this helps and Happy Fucking Boys