Harris is reacting to the movement under the covers ~ it makes a very good substitute for prey
![Laughing](images/smilies/icon_lol.gif)
All Harris is doing is practising predatory behaviour & cats naturally hunt by waiting, watching & ambushing. They can remain absolutely still but be like a coiled spring with full attention focussed on where they think the "prey" is ~ it's called "interest in a locus".
The best way to get Harris to stop doing this is to direct the "play" to something more appropriate & to avoid, as much as possible, any reaction when he does attack.
Firstly, just in case you do, I would suggest that you completely stop using ANY bodyparts to play with Harris ~ no hands, fingers, toes etc.
The get some "fishing rod" type toys to use instead. They don't need to be the expensive ones from pet shops; just a length of cane with some string tied to it, then something to grab tied to the string, e.g. screwed up paper, a piece of furry fabric.
Use these toys to engage Harris in play so that there is no association between your body parts & predatory play behaviour. And stop all play sessions in the bedroom ~ only play in other rooms.
Have a good play session with Harris sometime during the evening, but well before you go to bed & he starts on your partner's feet! You don't want Harris all wound up & playful just before you go to bed, so give him plenty of time to relax & calm down before bedtime. Perhaps give him some of his evening meal just before you go to bed ~ a full tummy can help cats to stop playing (provided there's nothing to play with!).
When in bed, if Harris does try to attack, do your best to show no reaction at all. If necessary wear thick socks in bed so that you are more protected & don't have to react to the teeth & claws. Keep as still as possible & certainly don't shout, squeal or make noises that are likely to arouse Harris' predatory instincts.
You could also try catnip toys ~ cats either react to catnip or they don't & if Harris is a cat that reacts to catnip, then toys stuffed with it are likely to detract him from feet under the duvet. Maybe try throwing the catnip toy away from the bed for him to chase.
It may take a bit of time before the feet biting stops, but the stiller & quieter you can be, the better.
Good luck.