So, we're bonding with the kittens, amongst other things, with string.
String in the hall....string on the bed....string in the kitchen...
I hadn't thought it through.....
... I just tried to do some sewing!
It wouldn't matter if you had used string to help bond with them or not, they would still be intrigued by you sewing.
I do leather working, and one of the things I do is lace items together, two or more pieces of leather with holes punched in them held in a clamp between my knees. A long piece of leather lacing thread getting flicked from side to side as I carefully do each stitch making sure the lace doesn't twist. Then I happen to look down away from the work for a moment and see this little black and white face staring up at me in avid fascination of the lace moving across my kneecaps. Up to that point i had never thought that lacing leather items could count as an 'extreme activity', the Adrenalin flowed as with each stitch I expected to feel tiny daggers enter my knees.