According to the internet:

The Riker Maneuver refers to a tactic used by Commander William Riker in “Star Trek: Insurrection,” where he collected metreon gas to create an explosion that damaged enemy ships. It is also known for describing Riker’s unique way of sitting in chairs, where he swings his leg over the back.

I guess it must not be the gas one, he’s too classy to stink up a restaurant