Sand Gravy
When you go to the beach and get sand in your vagina. Then you have sex. The resulting splooge - sand mixture is referred to as sand gravy.
Man, I wish we'd played volleyball in the gym instead of at the beach, because this sand gravy really chafes.
Sand Gravy
When your dog goes to the beach, drinks too much salt water and has watery, projectile diarrhea.
My dog is so stupid, he drank too much sea water and shit sand gravy all over the back of my car on the way home.