To solicit sexual activity through facebookwall posts. Like a "booty call," it occurs without warning. The person soliciting sexual activity usually implies that their place is available for the other to stay anytime (for casual sex).
This guy that I haven't seen for ages just bootywalled me on facebook!
it derives from the urban vernacular suffix of "wack" meaning undesierable and the negro prefix of "booty" meaning foul. it means something that is worese than "wack" and as dirty as "booty"