It is a joke meant to embarrass you. :) If you spell out "ICUP" out loud, you say "I see you pee" which is a little bit gross. The person who asked wants to embarrass you a little bit. I hope you found this useful! :)
@holaitsanna true. We play this joke on each other usually as kids, because most adults know it. If you find an adult who doesn’t, well, it’s time to get them with the joke. Also, you can say “spell pig backwards & add funny at the end.” Gee, I pee funny. (gip funny). Gee is like omg.
Another one is to tell somebody to look down their shirt & spell attic. A t t I c - a titty I see
And if someone is pretty bad on the computer and asks, what’s wrong with this dumb computer? You can say it’s ID ten T error. Or ID 10 T. If they don’t get it, have them write it down - id10t which should look like idiot. Which means stupid. Just a funny joke with friends. I wouldn’t do this to your boss.