I used to go jogging once a week or so at a gym with a friend of mine. For several weeks, he would wait outside while I took a shower. Then he started taking a shower with me. The first or second time he did so, while we were standing there at adjacent shower heads, he said to me (about his own very small cock, just out of the blue, with no preparation or context for it at all), "it gets twice as big when it's hard." Without missing a beat, I said (about my much, much larger flaccid cock), "So does mine" and then changed the subject. (This wasn't true, of course; mine gets about 50% larger hard than flaccid. I wasn't trying to lie or brag, I just said the first thing that popped into my mind to get past the awkward moment as quickly as possible.) Neither of us ever mentioned a word about our own cocks, or the other guy's, ever again.