THIS IS NOT A JOKE!!!: How can i knock my mouse out without killing it and neuter it at home?

I'm sorry, but that's a bad idea. You could easily kill him, since you aren't legally licenced. You should've checked the new mouse's bum before you left the pet store. Its obvious if its a male..please, do not attempt this. Why not just set up a new cage, and get him an actual male friend?