Bareback rules?

[Hornyone]

Depends on the circumstances, if your in a sauna in a public sling then you take what ever comes, but hook ups are totally your choice who you let fuck you!

[LetsPOZBreed]

Seriously, this can't be said enough:  CONSENT, CONSENT, CONSENT!

I think there's a clear difference from those who have said things such as: that you should just go with it; the guy is probably a good fuck and is just having a little fun with you; his attractiveness isn't really an issue, etc - and actually attempting to take away your ability to consent to letting him inside you.

You are the guardian of your own hole.  You decide who you let inside of it.  You decide who will never go near it.  No man is "entitled" to be inside you any more than you are not entitled to every man's cock.  

Even in true Dominant/submissive and Master/slave scenarios, both partners (ideally) have had long discussions about what rules apply to their situation.  Every couple is different; your rules with Guy #1 can be totally different to your rules with Guy #2 - it's just in how you connect with one another.  But rules are MUTUALLY agreed to...a true Dominant man would not want to break any of your stated limits, and will ask you to specifically state what those limits are ahead of any play session.