FINALLY got it! You have to RIGHT click (rather than left) on the item WHEN it's in the inventory, and KEEP right clicking until it says "use." This is odd, because all through the game up until this point, you just left click on it to use it. Anyway...finally got Hopkins dressed up and past the security guard....woohoo! This seems to be a pretty decent game so far, but definitely an ADULT game.
PLAYING ON PC: World of Warcraft...nothing else...there is no need for ANY other game when you have THIS one to play!! LOL