When you have anal sex with someone, who produces a lot of mucus out of their arsehole, and it gets up your urethra and seeps out when you have a slash, like you have some horrible STD discharge. (Can be mistaken for snot cock, when you sneeze in your own hand and then proceed to masterbating with the same hand for lube, post-nasal pleasure)
Uh! you dirty fuck! youve gone and given me a weepy peepy. Go wipe your arse out and we will carry on.