Similar to a titty fuck, only the roles are reversed. Two men and one woman take part. The two men hold their erect penises about three inches apart, while the woman takes one breast and manually shoves it in and out of the space between the two penises.
It is unknown whether any woman actually gains pleasure from the converse titty fuck.
A: "Yeah, I thought she wanted a threesome, but really she just wanted a converse titty fuck!"