Suddenly nipping

Hello,

My cats aren't always allowed to sleep in my room at night - but sometimes they are.
Cosmo is fine and sensible; choosing to sleep at the end of the bed. But Iggi always wants to be as close as possible, hence why they don't always get to share the bed all the time!
Recently when they have been allowed Iggi has taken to in the middle of the night trying to get in under the covers beside or behind me, purring extremely loudly, dribbling and nudging me with his wet nose. Then (after a short while of that) he'll open his mouth just a tiny bit and pinch really quite hard, not letting go - but he's still purring and seems content.

He's always been a cat who doesn't understand "no", the one who scratches the furniture and wallpaper, and the one who walks on the kitchen counters where he shouldn't.
He's the one who shouts at me to wake me up in the morning when they are shut in the kitchen (their bedroom). And that's whenever he feels like it, not necessarily when it's time to get up, which is sometimes how he ends up in the bedroom.
He's also the one who has tummy troubles and has to take medication to 'keep him regular'.

Any ideas? He's a rescued boy, about 10 years old by the way and he's been with me since he was about 6 months old.

I would have the vet check his teeth.

Thanks for the suggestion.
He's just had his annual check up last week and the vet said how good his teeth were for his age. My other cat, Cosmo, may need some dental work eventually but Ig's teeth are fine. I suppose that's the upside of his love of dried food!

Hmm, throwing him down off the bed whenever he does this may eventually get the message through to him that it is not acceptable behavior!