Black Triangle 

The action of walking into someone in the shower, where you don't quiet see the person's naked body, however you do see the outline of their public hair (especially in females) in the form of a black triangle.

Dude! He walked in on me in the shower and saw my black triangle. And just kept staring!

Her black triangle has clearly been shaved off.

Black Triangle by Whatever loser March 24, 2011

Inverted Black Triangle 

Like the inverted pink triangle, only representing lesbian pride rather than gay male pride.

She was proud of being a lesbian, and had no fear, so she wore the Inverted Black Triangle around her neck on a chain.

Inverted Black Triangle by S2G-Unit February 24, 2005

Triangle back 

When a girl has shoulders like a bear that are fucking wide as hell and a tiny ass waist that doesnt match up at all. WHAT THE FUCK!

Crystal Weigel is a fucking triangle back

Triangle back by Bobbbbbbbbbbbafhjiawhfvaiow;'g January 16, 2009