Fruit machine lurking

I was in pub with wife and noticed person watching other playing slots.

I am sure there is an actual word for this my wife thinks lurking but it's not that. It defo ends in ING

Loser-ing? Weirdo-ing?

Not talking to wife ing?

We need a new word to cover this phobia.
I suggest "slurking"

ps Afterthought....."furking" :wink:

I'm pretty sure it's lurking. But that's just based on an episode of friends.

Scooping? Or is that just for emptying it? Do also remember there being a word for it though.

Boot him in the cherries or hit him with a bar.

I'm thinking it's Sharking