Mine always come in the bathroom with me. I can never go potty without at least 2-3 'supervisors' to make sure I flush properly. LOL Bear & Sabrina help me shower, Sassy helps me brush my hair, and any of the are likely to help me brush my teeth.

In response to the OP's orignal topic, I figure your kitty comes in when you're going #2 because you're staying in one place longer and more likely to either provide a lap for a bit, or a bit more petting time perhaps? Dunno for sure on that one.