Wielding the sarissa in synaspismos, again

[Jim Webster]

Clearly it can be done!

https://thegailygrind.com/2014/04/12/attention-nude-sports-enthusiasts-watch-naked-man-ride-horse-bareback/

Roy

Because he's riding without a saddle, he seems to be using his knees to brace himself, and that might allow him to keep just above the horse's back.
Dunno, but I'm not trying it.
I suspect he's an excellent horseman