Hi Hippyhound,
For a Stallion to climax, all he needs is to be in the mood! A Mare in heat, close vicinity, is for most Stallions, a MUST!
Depth has nothing to do with it, nor does experience or in-experience!
The Stallion does not have to insert his full penis into Mare or anyone/anything, to orgasm.
It comes down to Technique, when you're manually trying to make Stallion orgasm,
blow job or hand job.
If a Stallion started urinating, while I was playing with him, I would more than likely aim his cock towards my breasts and enjoy the warmth of it pouring over my body.
As I've done with a Cow, who started urinating, while I was orally pleasing her. Also allowed Cow to defecate on my chest. As they say, shit happens, especially with farm animals!
Ms_Beast!