「Orifice」with「meat」as it refers to thick-bodied, sluggish LARVA of certain insects, such as maggots eating their way into a meat hole.
Silk moth caterpillars with SCREWING, TWISTING motions within a cocoon built TO SURROUND themselves until metamorphosis, at which time the cocoon is EMPTIED. Refers to the SPINNERET of the caterpillar which spews a constant stream of wet, sticky, stinky silk from within its body meat out of an orifice at one end. Freshly-spewed silk is fairly stinky in fact. A single continuous fiber is used to construct each silk cocoon, averaging 1,000 meters in length ( 6/10 of a mile or so) wound in hundreds of thousands of「twisting, screwing」figure-eight shapes. The fibers consist mainly of two fluids containing proteins: fibroin which is the odorless strong core used to make silk, and sericin which is the sticky, stinky glue-like substance that holds a cocoon together and is supposed to be washed away prior to spinning the fiber into thread.
「Meat orifice」equates to the silk caterpillar's spinneret as a male's PENILE MEATUS that spews semen ejaculate and other emissions while in「screwing, twisting motions to empty」the contents. Wormy appendages eating their way into a meat hole, and spewing stinky silk, are obviously analogous with reproduction: see 糸 for details.
Perhaps「mouth meat」as LARVAE that have only one purpose until metamorphosis, and that is to eat and grow meat. Insect larvae were most certainly a food source generally for early humans, containing about twice the protein of pork with the added benefit of remaining alive in your lunch pail, staying relatively fresh until consumed and popped into your mouth like a snack food. Early human societies likely all ate insects and grubs as do many still today in Australia, Africa, Southeast Asia, China, Japan, and Mexico, for just a few examples. Some sources suggest this glyph means「round」and most「orifices in meat」are in fact so, as are most maggots. An「orifice with meat」inserted will generally assume a ROUND shape.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: a small worm; to twist; to surround; empty
Japanese EDRDG: a small worm, to twist, to surround, empty
Unihan extended: a small worm; to twist; to surround; empty