It is a good thing that Tony Stewart and Kevin Harvick are good friends, or this could have turned out much differently.  Because I know very little about NASCAR, I will let the folks from Tire Ball explain:

Delana Harvick was victim of Tony Stewart’s latest “good luck grab” during the pre race at Chicagoland Speedway this afternoon. Stewart, who has a ritual of walking up to someone and grabbing their behind during pre race says he does it for “good luck”.

Delana has joked numerous times on the radio about how she needs to avoid Stewart as she has fallen victim to his behind grabbing more than once.