It is the lesbian version of "titty fucking". Instead of a penis sliding in and out of a cleavage it is the act of two sets of tits weaving in and out, rubbing nipples, etc.
"Last night me and my girlfriend were titty weaving and it was awesome"
"She has big tits, I really want to titty weave with her because I'm a lesbian"
"She has big tits, I really want to titty weave with her because I'm a lesbian"
by Lala & PB March 16, 2013