In my opinion (which probably only really has meaning to me, but I'll share anyway)....
I think you are better off just being PSE for a serious boyfriend. I just think there are too many risks involved in being that filthy with a lot of men.
Personally while PSE is totally HOT, I like a nice combination of GFE/PSE to balance it all out nicely...
PSE: (In my opinion)
*Lots and Lots of filthy dirty talk, nasty hot dirty talk, possible need for her mouth to be washed with soap afterward LOL
*Blowjobs (down & dirty, spitting on cock, using 2 hands while sucking, etc) where he can cum in your mouth, on your face, tits, ass, hair lol
*Fuck in cunt/ass with Cum in cunt/ass, face, mouth, dog dish (then licked clean lol)
*Ass to Mouth (Fucking/Sucking)
*Snowballs
*Double Penetration of both holes or Just one hole getting DP'd (ouch lol)
*Multiple positions, hard fucking, not that "making love" stuff
*Typically everything is uncovered/bareback
To boil it down....watch the nastiest porn video you can....that's my definition of PSE and one that I think should be kept for a more serious boyfriend and not so much for the "casual sex" thing. One whom you trust and feel very comfortable being that filthy around, and consider the relationship to be one where your health is not in danger if you engage in such activities.
BUT
That is just my opinion, and not the opinion or views of everyone.
Whatever you feel comfortable with....Do!
It's your body/mind, and you make all the decisions about what's a go or not.