Our cat has started something new: light bites that involve it's entire mouth.

The other nite, it clamped on to my sweater like that.  When I started to
extricate myself (slowly), it grabbed my wrist.   This thing's mouth was wide
open.   All previous bites have been more of a nip than a bite. This was a
complete mouthfull.

It's happened a couple of times since - always while laying in my lap and being
stroked.   My suspicion is that it's not yet fully desensitized to human touch -
in spite of seeking same fairly regularly - and the bite is kind of like the
reflex we have of raising our hand when a ball is suddenly tossed at us.

It's not a hard bite - seems more like a reflex that got damped because if it
had gone all the way and applied full force my forearm would be a mess.

If this is a communicative gesture ("Stop That!"), what's the significance of
the total mouthfull instead of a nip?

??