Plush it

Darren has been obsessed with flushing the toilet lately, so he flushes just to flush. When we are in the bathroom taking care of...um...business, he will volunteer to flush it. Except I think he is saying "Plush it." I have asked him repeatedly what he is saying and he just gets frustrated that I don't understand what he is saying. Is he perhaps combining the words push & flush? Pretty ingenious if you ask me!