With the right guy, I have no limits. But there has to be trust and a steady relationship, like a FWB. I can not do the one night stand things. Like I said, with the right guy, I would try anything. If I like it, lets keep at it. If I don't, then at least we tried it and now time to move on to the next trial.
My limitations have always been just mutual oral. I've never been fucked by, or fucked another man. Just two married guys not getting enough sex from their spouses getting together once or twice a week to suck each other off. I'm in my present 2nd marriage and I told her early on that I have and do enjoy sucking cock. She was understanding but did not want me doing so behind her back, she wanted to be present. We've had several experiences with a few guys and she's enjoyed the experiences greatly. All three of us get to suck cock and she gets fucked by two men. She doesn't always join in, but she wants to be present so she's aware of who I am sucking and getting sucked by. Our present regular friend is really turned on by the fact that a woman is watching and occasionally participating. He loves that fact that he can call to make arrangements with either of us knowing if all he wants is a blowjob he'll get it from just me, or both of us sucking him together.
We almost always share his loads unless one of us just swallows it all while deep throating his cock. All three of us have become skilled deep throaters on my 8" and his 9".
I would suck, fuck, rim, be sucked and fucked and rimmed. I guess my limits would be pee and scat play. No way would I ever get into that
I limit myself to oral and JO. I really like the feeling of a cock both between my lips and in my hands.