A cornstarch and water mixture used in thickening stews, sauces, etc. The term has been used by U.S. Army mess hall cooks, and it is presumably derived from its resemblance to bull semen.
Usually involves an extremely obese woman, a saddle worn backwards and a large didlo. The woman bucks wildly while the man tries to stay on by hanging onto a the dildo poking out of her vagina. There are no winners in this contest.