to insert; to put in (such that there is a snug fit); to have sex; to fuck; to pigeonhole (into a particular category); to place a ring-shaped object around something (esp. one that restricts freedom, such as handcuffs)
to inlay; to insert; to plug in (to a formula); to immerse; to trick; to deceive
to fit; to get into; to be fit for (a job, etc.); to be suited for; to fall into; to plunge into
to get stuck in; to be mired in; to be addicted to