Sorry if this seems an odd question but i've not experienced it with my other two so i didn't know why he was doing it.
Basically Ralph is a drooler, he can be sitting on my knee and when he leaps off i have a drool patch on my knee, it's the same when he lays in bed. It's quite a lbit of drool, at first i thought he was actually peeing on me/in bed but i've watched and have seen water droplets fall from his mouth. He does mainly do this when he's being stroked and is purring, is it just because he's excited and happy??