'sneak in' definitions:

Definition of 'sneak in'

(from WordNet)
verb
Enter surreptitiously; "He sneaked in under cover of darkness"; "In this essay, the author's personal feelings creep in" [syn: sneak in, creep in]
verb
Insert casually; "She slipped in a reference to her own work" [syn: slip in, stick in, sneak in, insert]

Synonyms of 'sneak in'

From: Moby Thesaurus