The guy knows his co-worker to be a normally conservative fellow, and is curious about his sudden change in “fashion sense.”
He walks up to him and says, “I didn't know you were into earrings.”
“Don't make such a big deal, it's only an earring,” he replies sheepishly.
His friend falls silent for a few minutes, but then his curiosity prods him to ask,
“So, how long have you been wearing one?”
“Ever since my wife found it in my truck.”