a tear of disappointment
A single drop of cum that comes out when a guy gets hard but then has to go to the bathroom. It's like his body being a traitor.
He got a hard-on during the meeting, but when he had to go to the bathroom, he had a tear of disappointment on his pants.
He was getting ready to propose, but when he had to go to the bathroom, he had a tear of disappointment on his shirt.
He got excited during the text, but when he had to go to the bathroom, he had a tear of disappointment on his underpants.