Sakura, my girlfriend's adult sister, works for an underwear manufacturer and makes me test prototype elephant briefs with a hole at the tip. I get hard in front of her and my glans pops out, ruining her attempt to collect data. She wraps her puckered lips around just the head for a work-related blowjob, licking and sucking until I cum in agony. Claiming the briefs will get dirty, she cleans me with her mouth, and I keep lending her my cock for product development.