Clam jouster 

Used to describe a lady who likes ladies, derived from the act of rubbing their pussies together.

Paula was a right clam jouster

Clam jouster by Funky the Monkey April 22, 2006

clam jouster 

A Lesbian

Did you know that she is a clam jouster

clam jouster by Rob October 31, 2003

clamjouster 

A lady, often but not uniquely, of Catholic education who engages in the time honoured Girls' School pastime of clamjousting. It is the noble martial art of clam-to-clam combat, where one girl grinds her clam against her opponent's. (aka Tribadism)

The collective noun is 'TILT' (From the medieval tournaments consisting of a number of jousts.)
"A tilt of clamjousters"

See also: boxgrazer, dieseldyke, mingeeta, rugmuncher, WRAC.

"That dorm has seen so much clamjousting the matresses squelch with fannybatter"

clamjouster by Cutaway August 17, 2004