I have heard some bondage tops recommend checking circulation if the bottom complains about numbness/tingling, because if circulation is decreased (indicated by delayed capillary refill, cooling of the limb, color changes, etc), they then feel they can chalk up the sensation changes to decreased circulation. Since short periods of decreased circulation aren’t really dangerous in isolation, signs of decreased circulation are seen as a reassuring indicator that the numbness is “just” due to reduced circulation and therefore is no cause for concern.

The trouble with this is that reduced circulation and nerve damage are not mutually exclusive, and in fact often happen together -- arteries, veins, and nerves often run in very close proximity, and the fact that circulation is impaired doesn’t mean that you can’t also have nerve damage occurring at the same time. If there is a way (short of hooking your bottom up to an electromyography (EMG) machine, which is used diagnostically to test for nerve damage and which I imagine most of us don’t keep in our toybags) to say for sure that decreased circulation is happening totally in isolation with no involvement of nerves at all, I don’t know of it.