Vibes for him. Hope it is all ok. Sometimes my Poppy gets matted down there as she is a lionhead and has long hair. It isn't helped as she sometimes also gets a mucky bottom. We've had her trimmed around there before, which has helped masses. Hoping d'argo is as easily helped.
It might be worth thinking about d'argo's diet if his is also caused by a mucky bottom. We've had to cut out all veg and cut down drastically on pellets to help Poppy. See what your vet says.