what would you do?

Has this happened to anyone?

Probably ask him if he needed a hand.

I'd ask if I could join, then drop my clothes, grab my cock and go for it. If he seemed comfortable, I'd offer an hand or my willing mouth.....

Nope, unfortunately never happened to me....

if he had a big cock I'd stroke him to Zooey Deschanel until he came.

Happened to me, but I was the naked guy...or teen. Older stranger stumbled onto me enjoying myself in the woods. After my initial panic, I noticed he wasn't leaving or looking shocked or horrified. So I got back to work and had one of the biggest orgasms of my young life. My voyeur smiled, and moved on, leaving me gasping, spent and covered in my cum. I get hard just thinking about it. :-)

that would be sweet. i'd totally watch.

I'd probably stay and watch, pull out my own dick and start stroking too.

pull my cock out and ask him to cum all over it

I did once when I was about 13. Often used to go to a clearing in the local woods where porn mags were left lying around. Went there one day after school to find a guy completely naked wanking over one.
He showed me the mag and I joined him! First time I ever wanked nude outdoors.

seriously...has no one seen any horror movies? he probably has his 22 right next to him. After growing up in Wisconsin I have learned never to mess with someone alone in the woods...run..run...don't look back

That said...always fun to watch someone jo. Even help a little.

I would stop and take my dick out, make sure he can see me, and wait for his reaction...

I agree, don't mess with someone alone in the woods, even if they have their pants down, and especially if they are jacking. However...I can imagine what I would LIKE to do.

I know of two or three places locally where men who like sexual activity with men go to have encounters & seeing someone wank there either watched or helped in some way by another male is perfectly normal..It is called a cruising ground & most areas have them..

There are a 2 or 3 around where I live. I've participated on a number of occasions. It does seem natural. What I like about it is that it's completely anonymous, all ages and types.

never happened to me.....id watch, see if he would react .....if he likes ,i pull my now hard dick out...get as close as he will let me