It sounds like maybe you’re describing scent rolling? That’s a wolf behavior which many dogs retain. Our mutt is an extremely enthusiastic scent roller as well. My understanding is that it’s really not all that clear from the existing research what purposes it serves in wolves. The most common theory seems to be that it may be a way to carry important scent discoveries back to the pack (food, rivals, dangers, mysterious novelties etc.), although wolves will scent roll when the whole pack is together too, and apparently individual wolves also vary quite a bit as to which scents they find worthy of rolling in, so that may not be a fully adequate explanation. Anyway, there are lots of videos out there of both dogs and wolves scent rolling, so you could check those to confirm if that’s what Taz is doing.