A sexual position in which the male is sitting and the female sits on his lap with her back facing him. For best results place a large standing mirror in a location easily viewed by the male so he can get a third-person perspective.
The position was named for "JimbyJimb" as it is his preffered method of achieving pleasure.
"Hey hun, what are we doing tonight?", "Why, the Jimby Special of course!", "Great, I'll get the mirror.".