I exited the lavatory, having just taken a leak, and there was a line of pax waiting.

Right after the next pax in line enters the lav and locks the door, the FA points to my shoe and says I have TP stuck.

Now I’m a dude and only went #1 so this is obviously not TP that I used. I was a bit at a loss for what to do. If the lav were unoccupied, I’d simply go back in and remove the TP (using a paper towel) and wash my hands again.

Do I kick the TP off my shoe and just leave it on the floor?

What, precisely, is proper conduct here? Fortunately I had an airsickness bag at my seat and hand sanitizing wipes in my jeans pocket, so I simply peeled the TP off my shoe with my bare hands and disposed of it at my seat. But what if I hadn’t been so well prepared?