Pumped by the Squid Lords. Commander Elena, #2

Lieutenant Commander Elena Vance thought she'd plumbed every horror the Atlantic concealed-until a violent undertow sucks her into a lightless trench, and she awakens in the breathless air-pocket of an abyssal cathedral. Here dwells the Cephalon: mermen warriors with scaled, statuesque physiques crowned by writhing squid-tentacles that taste, tease, and possess with inhuman precision. Trapped in their phosphorescent grotto, Elena should fear the wet, undulating caress of their suckers against her skin.
Instead, she finds herself mesmerized by the alien hunger in their black eyes and the obscene promise of those searching, muscular mouths...