Sounds like he needs to wear his gag, nipple clamps, and handcuffs for a video chat with you and apply the clamps and cuffs with the chains intertwined so that if he moves his arms too far from his body, his nipples get a nice tug. Of course, the gag may make it difficult for you to understand what he's saying but he can always type his responses, right? It would be up to you how much you'd allow him to hunch over before reminding him to sit up straight (or as straight as he can) while he types...

Newer dominant here, (and first time commenting) so I hope I explained the clamps and cuffs connecting in a way that makes sense :)