An SBGer is an acronym for sneaky biddy grabber. An SBGer sneaks around with his/her biddies. The SBGer doesn't tell his/her friends when he or she is going to hang out with a biddy and tries to keep it secret. Also commonly associated with creeping. An SBGer can also be described in the act as SBGing.
"John is such an SBGer. He is always sneaking around with Caroline and Melody."