I did not know this about cats. I found this on someone’s blog:

“strangely, did you know for cats a slow eyeblink
is a sign of affection? i do it to dingis and
dopey a lot. usually they do it back, if it’s an
unusually powerful slow blink they’ll jump up
from what they’re doing and come snuggle.
…
anyway, i find myself doing that more and more to
people instead of just cats.”