Synonyms of sneak in

Verb

1. sneak in, creep in, penetrate, perforate

usage: enter surreptitiously; "He sneaked in under cover of darkness"; "In this essay, the author's personal feelings creep in"

2. slip in, stick in, sneak in, insert, add, append, supply

usage: insert casually; "She slipped in a reference to her own work"