The action of inserting one's hand into another person's armpit and rapidly wiggling as a salmon would wiggle it's tail when swimming. Simultaneously shout 'sneaky salmon' to notify the one who is being sneaky salmoned.

The act of putting a live salmon down the back of someone's pants, then yelling "SNEAKY SALMON SNEAKY SALMON" and dancing as they struggle. Yes, you will be held accountable if you are caught sneaky salmonning somebody.

The action of sneaking up behind an unsuspecting individual and then inserting one hand between that person's knees and then slapping the insides of their legs while traveling upwards, mimicking a salmon swimming upstream.