It would be fun to meet either the group or (preferably) the group leader at
bucks or for a walk in the park just to become acquainted with the people and the plans for meeting up later - or even right after that first meeting.
I hope that the first masturbation meeting will be casual/gentle, not a whirlwind of testosterone. In my mind's eye, I see a group of people being thoughtful and polite, asking instead of assuming the person next to them wants you to touch them.