I agree that there is nothing wrong with that. We are grown men enjoying each other.
I have one good buddy, that is very regular , hes been married, now has a GF, but loves getting together with me, so we can enjoy some hot mansex. We are vers, so it goes both ways there. As I said, very enjoyable.I also see another guy fairly regularly, hes all bottom, another enjoyable connection.
Its all good as long as we enjoy, and its mutual.
I feel like this is slut behavior, but that is definitely not a bad thing. Being a slut, I feel, is broad. If you reserve yourself for friends or hookup with anyone who's willing, you're still enjoying sex freely and openly; which is what I would consider being a slut. There's nothing wrong with it, just keep doing what you're doing and use slut as a word of power for yourself!
I offer this even to friends who are married with women who don't like anal playing. They fuck me so good and care about me at the same time.
Some couples give me the same opportunity, they let me playing botton with man and toping the lady. That's heaven on earth for me.