The act of pouring a shot of Jägermeister over a girls breasts before placing your face inbetween said breasts, turning your head side-to-side and going "BRRRRRRRRRRRRRR".
Dude: I heard you did Jägerboats last night!?
Bro: Yeah, I poured my shot of Jäger on her tits and motorboat
ed the shit outta her.