Tally up one more grower.
Halx - I understand what you're saying, and yes, penises DO all grow when erect. What he is referring to is... a "grower" has a penis that at least doubles or triples in size while erect, while a "shower" (rhymes with grower) is one that simply goes from say, 6 inches flaccid to like 9 inches hard. Basically, guys that are well hung when flaccid "show" more of their overall dick size, whereas growers might appear to be small while flaccid but grow to be just as big as the "shower" when both are erect.
(That was probably more than anyone needed to hear... but I just wanted to clear up what I'm perceiving the debate or question to be about... I've had this conversation with some friends, male and female, so the terms are pretty familiar.)