Using hairify as representation of flow. The trick is by using a rod as hair shell so that the hair extend inwards.

Cut the center piece to free the strings, Then use a blowdryer to soften the strings. Stir the strings before it cools down. You need a good printer and a lot of patience to work with the lite version, so choose large version.

Remixed from [by twinpic] Playmobil Toilet https://www.thingiverse.com/thing:1958958 PS: can't really find how to add remix from another site.