To clearly answer the original question - no, it is not possible at the moment.
If you do not wish to make a review, but only want to try out some variations just use the analysis tool. Just navigate to the desired move by clicking the arrows below the board and click away, you will automaticly create variations, that are not shared, unless you want to. If you want to, just give it a name and click share.
And don't worry about it, chances are nobody will even see your boring, biased and completely wrong review, unless you share it on the forums