twinasy 

A fantasy of having a threesome with twin sisters

I have such a twinasy of banging her, and her twin sister

twinasy by Ta Leo...ggrrr!!! October 21, 2023

Twinsync 

Being so in-sync with someone, you could be twins; alternatively defined: the moment when, in two separate places, twins do the same thing at the same time.

Abby and Lily were so twinsync, they readily completed one another's sentences.

Twinsync by 2NMom August 22, 2011