For me butt burn is usually caused by physical action ie wiping to much or too hard, or cleaning to much can dry the skin out. Sometimes of you have a bit of leakage (perhaps trying to pass gas) that can also burn... But 9 times out of 10 is because I wiped too hard/much. Gently blott.. if you must, apply cream and then wipe that off. That helps clean and also moisturisers. Try to treat your butt like you eyeball.... Touch it gently. Will probably make the world of difference
As for the being gay thing.. bottoming is probably not an option.. Not only for the above reason but can also do yourself more serious physical harm.. many docs don't even like to give prostate exam with a finger. I will say I'm a straight guy without experience of this, but I've seen plenty of posts on this forum about it. It's still perfectly possibly to have a loving fulfilling relationship though, perhaps hunt down Heath or one of the others and I'm sure they would be happy to chat (he has posted on this subject a couple if times from memory)