Ruined from behind 3 times in a row face down ass up

Description: My sub is on all fours face down ass up with his balls tied up behind him and a spreader bar between his ankles keeping his legs apart. with his cock and balls on display behind him i take advantage of the easy access and milk his cock between his legs, edging him close to orgasm and frustratingly ruining it at the last moment 3 times in a row, leaving his cock to twitch and fire out the spunk unattended below him and give it a few good slaps of encouragement. after the third ruin he is very sensitive and throbbing but i keep stroking the cock while he moans and winces for some post orgasm fun. to end the milking session i plug his ass and leave him restrained for his cock to calm down to a suitable size for locking back in his chastity cage.