(V.) to old greg on someone is to hit on someone very creepily and awkwardly, usually in an attempt to get that person to do something he or she doesn't want to do.
Effective examples of old gregging iclude:
1. throwing out continuous strains of awkward, senseless questions, such as: "do you want to go to a club where people wee on eachother?" or "do you ever drink Bailey's from a shoe?"
2. Displaying the mangina
Person A: Yo man, I saw you old greggin' on that chick last night. Did she give you what you wanted?
Person B: Nah, dude, but I bet if I had given her some Bailey's and shown her my artwork, she would have complied.