I am a non-native speaker from Germany. In German there's one idiom that goes:
Sich die Eier schaukeln
Literally translated, this means "to rock the eggs", where "the eggs" are testicles. This is used to express severe boredom, especially to describe procrastinating or one's state of mind when you should be appointed to a task, but aren't.
It is somewhat vulgar as it involves testicles, yet it is a widely used idiom which would not actually be perceived as an inappropriate thing to say in general.
I searched for a translation that would fit and found:
(from Urban Dictionary). Now I would like to know if this is actually a common thing to say and whether there are any alternatives that are more suitable for daily use.
Best Answer
"Fuck the dog" (or its milder variant, "screw the pooch") comes from an old joke.
Reddit
It is certainly not about idleness, but epic failure to get a sequence right. Janus Bahs Jacquet's suggestion of using the literal translation of your German idiom is probably a lot closer to the mark for what you need. If you want something a little more sanitized, try "scratching our backsides*" (or use another body part to replace "balls").
*originally I had "heads" here, but Janus points out that that strays into a different meaning.