If a guy invited me to have a shower with him, I would think that something sexual was involved. Most showers are not that huge, and the closeness of the nakedness is basically an invitation to have sex. I would feel my way around in the shower with him, but to be honest there is no likelihood I was invited in there just to have him say no to sex. However, on the one percent chance that he was completely bat-shit psycho and did say no, I would not press the issue.
"Never trust a fox. Looks like a dog, behaves like a cat."
~ Erin Hunter
~ Erin Hunter