Prompto convinces Gladio to do a little modeling for a photoshoot for whatever reason. Gladio agrees and expects Prompto to be all blushing and stammering throughout the whole thing. Instead Prompto is very focused and determined on getting the right shoots, and making sure Gladio is posed perfectly. So Prompto has no problem manhandling Gladio into position, arranging his hair, or clothing. Be authoritive when telling Gladio to hold still, move so far to the right or left, etc. . .

Gladio is stunned by this, and finds this side of Prompto extremely hot. Now he's struggling to hide his boner, and figure out a way to get Prompto to act like this and order him around in bed.