Green’s Dictionary of Slang

whippets n.

also whippet
[as dispensed from a can of whipped cream]

(drugs) nitrous oxide.

[US]Eble Campus Sl. Nov. 6: whippet – an indefinite amount of dinitrous oxide inhaled from a cannister to produce a state of euphoria.
[US]Abel Dict. Drug Abuse Terms.
[US]ONDCP Street Terms 22: Whippets — Nitrous oxide.
[UK]T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Whippit – nitrous oxide container.