You can, but why not wait until the blooms have faded? That is when vegetative growth is at its most vigorous. Trim at a point just above a rosette of leaves.

thanks, akamainegrower. The only reason I'm thinking of cutting them back now is because I had read somewhere that if you cut them back too late after they are done blooming there won't be many blooms next year because you will be cutting off next years' buds. I just thought maybe it would be safer to cut off some of this year's flowers before the new buds begin. Hope I make myself clear.

The flower buds for next year will form in late summer/autumn. You will potentially lose the flower buds if you prune then, but not if you do it by roughly the end of June.

Some say you can't keep rhodies small. That pruning leads to (undesirable) rampant growth at the cut site. If you get this, it's best to remove, say, half of the new tender shoots.

You can also move it to where it has more room and you don't have to prune it. They take to being moved rather well.
Mike