Definitions by SHTH34D
Slappies
When two men are at adjacent urinals, it is common courtesy to ask if the man next to you needs slappies. Slappies is when you assist another man with "shaking the dew off the lilies" so-to-speak. You slap the man's d*ck to get the last few drops of urine out for him. It is also common for the slappee to ask the slapper if he would like slappies as well.