Getting your pets stoned is a most fucking immature and irresponsible thing to do to them. If you do that you shouldnt even have pets. If I ever saw someone doing that to their companion animals I would pick them up and take them home after splitting theirs owners lip open.
Goddamn where do I even begin describing why that is so dumb?
Buy some friggin catnip pal.

It ain't cruelity in any form no matter how you put it.

My cat loves it and insists on hanging with the lads. I wouldn't let a hair on her head be harmed by anyone, if I have compassion for anything in life it is for animal kind.

I don't actually give her 'blow backs' though I have seen it done, she just gets stoned on the fumes and a cloud of smoke blown in her direction every now and again for good measure!