the same as a dirty sanchez, except instead of solid feces, you use fresh diarrhea, causing a drippy wet affect on the upper lip, and possible turn off...
ay carumba amy said pablo gave her a wet sanchez and it dripped into her mouth, yuck!
A combination of a wet willy and a dirty sanchez, with the offending finger being directed to the victim's ear canal, as opposed to the upper lip.
As a prank, the benefit of a wet sanchez over a dirty sanchez is that any clinging fecal material may go unnoticed for a longer period of time due to distance from the olfactory senses.
There's nothing better than spending a day at the hospital giving paraplegic patients wet sanchezes.