Idea but for a double sub play (remotely) ;-)
1. Locking collar, chastity and gag locked for both sub 
2. Handcuff on
3. A chain or rope is tied to the ball pass over the handcuff and then to a weight. 
4. Both sub on a video call with Sir 
5. At go both sub must raise the weight from the ground, this will pull on the ball of the subs the one that stay the longer win :-)

Win what ? That up to Sir to decided :-)

Predicament, physical trainaing and bondage at the same time !