I've always feared hitting on an woman, only for her to give me the "loser line" instead of her real number. Does anyone know the exact phone number? I hope to put it in my contacts so that I can know the second some unhonorable shill tries to give to me and so I can shame her.

You won't find find the Loser Line number online or hear it said on-air because it isn't real. Practically every "skam" or "skit" on the radio is 100% fake because you need permission to put someone's voice on the radio and many refuse after sounding like an idiot, so it's easier to just use actors. Call-in contests involving listeners are about the only real part left on morning zoo radio nowadays.

Does anyone know the number for the "loser line"?

Yes, any time you feel like calling and speaking with losers just dial 202-863-8000.