social top

That friend who always organizes social gatherings - they pick the restaurant, get a headcount, pick a time, make reservations, etc. "Top" here is a reference to the dominant role during sex, especially in the gay community. A social top is dominant in a social context.

I'm glad you are back from vacation - without our social top, we just sat around at home and wondered what everyone was up to.

social topping

Asserting your dominance in a social situation. Like being a top in a gay relationship, but in a social context.

"Claudia just told me she's gonna eat my leftovers in our fridge"
"Ugh, she's always social topping"