IIN to masturbate in front of your best friends?

It's not uncommon among young teens. Just a fairly normal part of exploring who you are and how the world works. If this is still going on in the late teens or adulthood, that suggests it has become a paraphilia.

Girls doing this can learn different techniques that might work better for them than what they've stumbled on by solo experiments.

For guys, it sometimes includes and element of competition: who's bigger, who can come farthest, who can come fastest.

That's pretty ignorant and childish, because we're all different and, in the end, what you do with what you've got is far more important that the equipment your genes have produced.

The Fastest Wank In The West competition is particularly dumb, since young guys should be learning how to control their sexual response and make things last, not training themselves to shoot at the drop of a hat. Not many women like to be with guys who come in five seconds.