Top definition
Having half an erection at the thought of something quite arousing. Not quite full blown but at the same time not quite a flopster.

Other words can be used in replacing cranking, including:

-Nursing
-Pending
-Streaming
etc.
The girl walked by and the boy smiled, only when she looked at him with disgust did he realise he had been cranking a semi.

Ted studdied the Bellaby Continuum with pleasure before realising he was cranking a semi.
by twkomg June 24, 2008
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