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.