I don't really know how to translate ネコ吸い, literal translation would be cat sucking/inhale but that sound weird, so I decide with "sniff cat".
If anyone have better translation for it, go ahead and fix it.

ネコ吸い or 猫吸い or nekosui is the act of sticking your face to a cat (usually belly) then breathing/sucking/inhaling.
You can google it or search youtube with keyword `猫吸い` to see how people do it.
pixiv also has a tag for it https://www.pixiv.net/en/tags/猫吸い

Akatori2st said:

I don't really know how to translate ネコ吸い, literal translation would be cat sucking/inhale but that sound weird, so I decide with "sniff cat".
If anyone have better translation for it, go ahead and fix it.

ネコ吸い or 猫吸い or nekosui is the act of sticking your face to a cat (usually belly) then breathing/sucking/inhaling.
You can google it or search youtube with keyword `猫吸い` to see how people do it.
pixiv also has a tag for it https://www.pixiv.net/en/tags/猫吸い

Cat huffing.