Slovakian Jack and Jill

When you and a partner conjoin into one ball of sexual operations and do 69 whilst rolling down a hill.

Person 1: Yo you know Shaniqua over there?
Person 2: Yeah she's my sister, why?
Person 1: Oh shit haha I took her to Pride Rock and we tried the Slovakian Jack and Jill last night.
Person 2: That's my sister what the fuck is wrong with you?!?!?!