Drool...yeah I know it's not necessarily the best topic, but the other day I was in pony role and we went all out with show harness and special show bit. My "show" bit is quite the contraption and takes a little while to get on (or off...which can be annoying when I just want to be done) because it attaches to my tongue piercing (it has to be screwed on which can be challenging: your mouth only opens so wide and it now needs to fit a bunch of fingers in addition to the large bit).
Note: the photo at right is not my show bit; it is merely a high port western bit. I used that photo here as an example of drooling. I will try and get a photo of my show bit up in the near future.
Anyway, the design of the bit drastically limits movement of my tongue. Coupled with how far back in the mouth the bit sits, this causes copious and uncontrollable drooling. As a pony, I really don't like this and find myself obsessed with trying to control it and wipe it off. Obviously my attempts were completely ineffective, but I just could not help myself.
My trainer really enjoyed all the drooling and, even more so, my obvious discomfort with the drool and my futile attempts to stop it and wipe it off. In fact, I found out after the session that she also liked having the added opportunities to "correct" me that were afforded her by my drool-related distraction.
Now I know that the drooling can emphasize the helplessness of the pony's situation and even add an element of humiliation. However, for me it really is an annoyance. I don't really feel humiliated by it, albeit it is occasionally embarrassing depending on whom else is involved in the scene, rather, I find the annoyance factor takes away some enjoyment of the feeling of helplessness.
I wonder if there are bottoms, specifically ponies, who feel the same way about drool. Interestingly, I know that when I am the top, I do find drooling sexy to a degree, so I guess it's just a matter of perspective.
As a bio-horse owner, I know that horses will also salivate a fair amount in the bridle and will often foam up when working. So, I guess this aspect can add to the realism of pony play. I do know that ponies will also get foamy (for lack of a better word) when being worked hard.
Usually drooling is not much of an issue for me with most bits and gags even if they are tight. So, when using my show bit again recently, I was reminded how big a difference it makes when a bit restricts tongue movement.
If you want your pony to drool, use any bit that keeps the tongue down. The best example here would be just a normal bit gag with a rubber tongue port attached (top right photo is a close up of this arrangement: a simple rubber bit gag with an attached rubber tongue port (the latter can be purchased for around $2 at most tack stores)). This combination causes a ridiculous amount of drool, on par with my show bit. Just be prepared for your pony to have a dry mouth at the end.
Here I am (below photo) wearing the bit gag with attached rubber bit port from the photo above. From the photo above you can see that most of the bit port extends into the mouth, which holds the tongue down and causes drooling.