What is gay zipper sex?

What is zipper sex?

Hurried sex where the clothes are not removed, and only fellatio is done.

Definition

Usually denoting quick sex, mainly oral sex where only the zipper is actually undone, the penis removed, and sucked on.

Noteworthy: Associated with Hustlers, who will reach into a person's pants, and jerk them off, for a reduced fee. Mainly done in dark secluded spots like back alleys, or in doorways of closed business shops.