I don't carry a BUG, but if I did it would be a J Frame in my front pocket in a DeSantis Nemesis pocket holster - in fact that is my primary CCW and that's how I usually carry it if it's not on my hip in a Kramer OWB holster. A M10 is a bit too large, heavy & bulky for a true BUG (hide-out gun) IMHO. If the M10 was your primary I could see it being carried on the belt as it is also too heavy big and heavy for an ankle rig.
This is just my opinion of course, but after carrying a CCW for 35 years I've come to know what works and what is really uncomfortable. My FIRST CCW was a 2" M10 and I sold it after a year of toting it around. It was just too bulky and heavy for the one extra shot advantage over that my M60-7. Yes, the J Frame takes a bit more practice to shoot well because of its lighter weight and smaller size, but well worth it IMHO.