1
general::
Phrase(s): slip in(to something)
to slide or glide into something, such as clothing, a sleeping bag, a tight place, etc. • I don’t want to slip into a cold sleeping bag. How can I warm it up? • I opened the bag and slipped in., Phrase(s): slip in (some place)
to sneak or go into a place quietly and unnoticed. • I think we can slip in the rear door unnoticed. • We slipped in and crept up the stairs., Phrase(s): slip something in(to) something [and] slip something in
to cause something to slide or glide into something. • Max slipped the bullets into their chambers and got ready to fire. • He slipped the bullets in silently.
McGrawhill's American Idioms And Phrasal Verbs