The Brown Bow
The Brown Bow is a way of showing extreme disrespect to someone, where the giver of the brown bow walks up to the receiver, turns around, bends over (or bows) and exposes their ass. Before the receiver can walk away the giver releases a turd, preferably dropping it on the receivers feet.
I quit my job today, my boss, Chris, is such a dick I'm going to give him the brown bow.
brown bow-tie
While crouched over your partner and receiving a hummer you defecate on your partner's neck, hence a brown bow-tie. Note that the person delivering the brown bow-tie must be facing his partner's head, lest he deliver a brown sombrero.
"While Sarah was giving me a hummer last night, those refried beans kicked in and I couldn't help but give her a brown bow-tie!"