When I take pills, I generally try to work up a bit of spit first. I'm not sure when I started doing this, but I can remember getting something super bitter (probably aspirin) stuck at the back of my tongue once, because it was damp enough to start the pill melting but not wet enough for it to slide on down. Ugh. It was HORRIBLE.
I've been doing this long enough that thinking about taking some pills will get the salivary glands warmed up, and the stuck-pill thing never happens anymore. (This is also handy when you need to take some pills and don't have any water handy.)
Well. Apparently it's even better-developed than I thought, and not completely voluntary.
I have some cholesterol pills I need to take every night. I've gotten in the habit of taking them when I take my contacts out, so that I don't forget.
Just now, I took my contacts out, and all I did was look at the pill bottle sitting next to my contact kit, and my mouth filled up with spit.
So yeah. Stimulus-response conditioning? Totally works.