Green’s Dictionary of Slang

creamstick n.

[cream n.1 (1) + SE stick/stick n. (1a); 20C+ use mainly US black]

the penis.

[UK]Farmer & Henley Sl. and Its Analogues.
[UK]A. Crowley Snowdrops from a Curate’s Garden 27: The engaging animal [...] exposed a superb and succulent cream-stick of some fourteen inches in length.
[US]Maledicta IV:2 (Winter) 192: Sometimes this process is combined with a reference to come-juice and coming – e.g. shooting stick or shooting iron, culty gun, cream-stick, cremorne = cream horn.
[US]R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].

In phrases