Getting a Flayer the Constrict and Jump skill would lead to a guaranteed Suffocate. Jump into position, use grab to pull in an enemy (if unable to jump to it) then constrict to force them to stay in position, setting up a suffocate for next turn. Getting another unit to cast Focus on the Flayer, would achieves the same effect.
One should be on their guard, when facing Flayers, as their skill Suffocate can easily kill your weaker units.
Flayers have moveable tentacles at their cock's head, preventing accidentally pulling it out. Their hands are rarely visible, being surrounded by long tentacles, they can give incredible handjobs.