I'll try to make this as constructive as possible.
I came onto my current job in a rotation program earlier this year as a new graduate out of college. In my short 6 months, I've done very little work and have constantly asked for more from my manager and other leads in my work-group. The only thing I've gotten is some easy admin work that took me no more than 30 minutes. Otherwise, my daily work is basically other administrative work that takes literally about 20 minutes a day.
When I started, my then-manager established no short-term or long-term projects, which didn't make for any short-term or long-term goals. I came into this rotation/job basically with a blindfold because I didn't have any say in what I wanted.
I try my best to come into work every day with a positive attitude and put in my best. However, my morale sinks lower and lower every week. I know there are plenty of jobs that take some time breaking-in, but I've already wasted half of this rotation already and I want to contribute. There seems to be little to no work to be delegated to me. The only thing keeping me sane is the handful of people my age whom I talk with and my venting when I get home every day.
Would it be unprofessional for me to talk to my manager how awful my 6 months have been? I've let him know through 1:1s that I'm twiddling my thumbs and I really need some work, but not my full inner thoughts on the job. As millenial-esque this sounds, I want to put in a request for another rotation already and quit.