Shego was an anti-villain who also happened to love and desire him.

Ron subconcious figured that if Shego was in love with him and wanted him, she would be less likely to hurt him. He also figure if he toggled the heading of villain into anti-villain it would protect him, not knowing what an anti-villain was.

In Shego's mind...

'Suddenly the little sidekick's looking hot. I could do things to his body he wouldn't believe, plus it would piss off the princess. But why am I feeling this, I went from wanting to kill him to wanting him. Something's going on and I bet that computer's the source since he was typing before I changed. I got to get it, but he could just type on it to change things... unless...' thought Shego as she noted two things.

One she could seduce him from the computer and wear him out during sex, then take the computer. Or she could use the container of lip gloss she saw on a dresser, the same lip gloss which contained the computer kid's knock out gas. Which would get the fresh meat and his little rat as well.