What would I be expected to do?

I am new to this and very intrigued about dogging.

I've always been in straight relationships, although I have helped guys' cocks enter my girl's pussyass by holding them.

I'm keen to get a blowjob by a guy but I don't think I could, either, give the guy a blowjob in return or kiss a guy. I'd be ok to give them a handjob, though!

My question is, and I hope someone can share some sort of answer with me, What would I be expected to do to a guy if I went to a dogging spot?
Also, if I was only brave enough to masturbate while some guys watch, how would I let them know this is all I am comfortable doing? (though I may also be ok for them to touch me a little bit....?)

Thanks in advance!