piss in someone's cornflakes

Verb

piss in someone's cornflakes (third-person singular simple present pisses in someone's cornflakes, present participle pissing in someone's cornflakes, simple past and past participle pissed in someone's cornflakes)

1. (humorous, idiomatic, informal, often, vulgar) To disappoint or irritate someone.
   • Sorry to piss in your cornflakes, but my mom's got asthma, so take your cigarettes outside.
   • Okay, now I don't want to pee on your cornflakes or nothing, but how exactly are we going to get up there?2018 November 17, “Food Hunt”, in Angry Birds on the Run, season 1, episode 2, spoken by Bomb (Baker Terry)

   Synonyms:

   burst someone's bubble, piss in someone's cereal, piss in someone's Cheerios, piss on someone's chips, piss on someone's bonfire, piss on someone's campfire, put a damper on, rain on someone's parade, shit in someone's cereal, shit in someone's Cheerios