Only My Mom: Sleep Over

-- background context --
My mom spoke with a co-worker earlier in the morning to inform him of a big decision she had made, and this is how she relayed that information to me and my sister.

Mom: "So I talked with Bill, it went well. He wants me to sleep over and talk to him tomorrow morning."
Sister: "...what??? Sleep over?!?"
Karina: "He wants you to SLEEP OVER?? Are you sure hahaha"
Sister: "Yeah, mom, it's sleep ON IT, not over. if you say he wants you to sleep OVER then that is just something entirely different!!"
Mom: "Gross! He did ask me if I found another man!!! Hahahaha."