The act of being in the 69 position and "checking the girl's oil" (insertion of finger into doodie hole). Then sniffing finger for purity. Checking anal viscosity.
The Bianchi Dipstick: That girl Jen looks pretty hot. I'm gonna give her a Bianchi Dipstick and check her 10w30.
by Pencil-Dick Jones April 10, 2011