Avoid looking

The quick glimpse at Laura's exposed intimates in combination with the previous study of her top was enough for Paul to notice a rapidly building hard-on. The only way to stop it is to avoid staring at Laura's exposed crotch, or any part of her, instead directing his gaze straight ahead at the elevator door.

"Well, someone is happy!" Laura remarked, standing up from her crouched position with a knowing smile, pointing at Paul's boner noticeably protruding through his shorts.
"I..th..this..isn't w..what you think" Paul stammered, growing red at this discovery despite his best attempts to hide most basic desires.

At just about that time, the elevator doors began to open and Paul saw this as a perfect escape from an embarrassing situation.
He hurried through the doors, only to stop short. This was the basement; he needed to be on the first floor to get out back to the dumpsters.