When you take a shower with a horny sloot and she reached around and gives you a handy with one hand and fondles your balls from between the legs with the other. This act is best when you use non-penis stinging soap as lube.
La Ducha gets its name because it is spanish for shower.
Jim: I got a La Ducha from that sloot named Karen.
Paul: How was it?
Jim: It was good, but the soap stung my dickhole.
Paul: Doesn't matter had a La Ducha
Jim: Yep :D