1. The act of sexually arousing a female by completely inserting one (or more) fingers into her vagina, i.e. the third knuckle.
2. The act of sexually arousing a man by the use of the hand, i.e. handjob.
1. When I went to drop off Suzie last night she started blowing me and she squirted all over my leather seats doing the third knuckle shuffle!
2. Maria and I were watching TV, and she wouldn't let me get into her panties but she did the third knuckle shuffle on me.