You’ve heard of the Mafia rub-out. This was the Mafia rub-up.

A gangland killer-turned-rat testified in Brooklyn federal court yesterday that Bonanno big Vincent “Vinny Gorgeous” Basciano once tested his loyalty — by having his girlfriend try to seduce him.

Dominick Cicale said that when he was a Bonanno wannabe, he met Basciano and his longtime mistress, Debra Kalb, at Bartinis bar in Forest Hills, Queens.

Basciano, he said, left the table and had Kalb “hit on me — rub my leg — to see how I would react.”

Cicale, 44, who passed the test and was welcomed into the Bonanno family, is in prison after confessing to three murders.

He’s testifying against Basciano, who faces the death penalty if convicted of ordering a hit on associate-turned-rat Randy Pizzolo.