[second narcotics sense fr the taking of LSD soaked in a sugar cube]
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with sugar daddy
A wealthy, usually older man who gives expensive gifts to someone much younger in return for companionship or sexual favors. For example, The aspiring young actress and the sugar daddy are a classic combination in Hollywood. The sugar in this term alludes to the sweetening role of the gifts, and daddy to the age difference between the pair.
[ Early 1900s