That one friend that's always on top of everything, he always has plans prepared, always ready to go out, always the social one, typically more extroverted than you.
"Ask Richard for tonight's plans, the dudes the platonic top of this friendship, I let him handle everything."
The one friend that you or someone else always follows around, they're usually the ones that come up with the plans, handle alot of the problems, and are generally atleast slightly more extroverted than you.
"I can't think of anything to do, I'll ask Richard, he's the platonic top of this friendship so he's most likely got plans for us.