A clear umbrella, the likes of which makes the wielder look like they are hiding in a condom from precipitation. The more people utilizing the awkwardly domed and transparent umbrella, the more ridiculous the scene becomes.
Person 1: It's raining awful hard, why not use my umbrella? There's room for two.
Person 2: I will not add more seed to the contents of your condombrella; I'd rather chance the rain.
Insult, directed towards men. Insinuates the person who it is directed at sucks penises, albeit in a safe fashion which just overall makes it even more humorous.