Making A Sissy

Yeah I'd figured that but I'm looking more for a where and a when.

I'd guess that it comes from the "sissss" sound of the stream of liquid. (Also USA)

I've never heard it here in Britain. It sounds 'baby talk'. In that case, our phrase is 'wee wee'. However, 'sissy' is a word we use - for a timid, non-daredevil type person, usually a child.

Half century ago in US elemenetry school playgrounds 'sissy' was a tease or taunt meaning, as someone above said, "for a timid, non-daredevil type person". 'Sissy' was thought to come from 'sis' which was common slang for 'sister'