「Mouth as prick is reamed while grabbed in two hands」or more hideous perhaps as「mouth used to cut prick by clenching while held big in two hands」but aptly describes a SUCKING SOUND, TEETH CLENCHING by the subject, or any witnesses. Refers to the sipping, sucking action and sound of pursed lips and clenched teeth in excruciating agony, or while noisily slurping or sucking something extremely hot from a cup, such as tea or coffee, or smoking something and taking a hit. The Chinese made the same sound when they witnessed someone else get whacked or whipped, or taking a hit, or when someone's mouth clenched on a tally. Note that in the West, you might say「ooooh, that's gotta hurt, Gene」and breathe in or out through pursed lips if witnessing a tough body check during a hockey game, or a knockout punch in a prizefight…same idea here.
　CLENCHING and related problems and fears are present in these glyphs:
　歯 and 齒 as teeth.
　恨 regret, hate, resentment, rueful, hold a grudge, malice, bitter feeling, rancor, to curse and swear.
　艮 chewing.
　仡 being fed up with conditions and bravely doing something about it while unafraid of the consequences.
　旡 suddenly choking on something in one's throat.
　兂 clasped with teeth.
　邪 wickedly demonic.
　拑 pinning with clenched teeth.
　音 loud noise.
　既 and 既 too late, happened already, unchangeable.
　茱 and 萸 bloody stump, dogwood.
　飢 ravenously chomping meat.
　啗 enticing lure, gnawing meat.
　啖 threaten a superior, taunt and torment, reckless endangerment while tasting and eating.
　猖 ferocious and insane, mad, reckless, not following the rules.
　惕 healthy respect of danger.
　𣇄 and 晣 biting off a chunk, bent by tonguing mouth.
　惮 and 憚 fear, dread, shirking, shrunk.
　喫 clenching with gasps.
　吃 and 喫 extirpate, destroy utterly.
　揕 bare-fisted jab, punch in the face.
　意 long in thought, intent, concerns.
　貇 tenaciously clenching jaw and not letting go.
　虞 horror, terror, terrorism.
　鉗 clamp and gag.
　𪗱 and 齟 discord, broken teeth.
　𪘚 and 齬 gritting one's teeth, great hatred.
　齭 pain caused by teeth.

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: variant of 吃
Japanese: to smoke, to breathe in, to inhale, to suck, to sip, to slurp, to absorb, to soak up, to kiss, to eat, to drink, to suffer, to receive, to take, to receive a blow
Unihan extended: eat; drink; suffer, endure, bear
EDRDG: consume; eat; drink; smoke; receive (a blow)