Flash him somehow

"Hey, I just realized I forgot to stretch before my walk, what about you?" You ask him.

"I, uh never stretch."

"You don't!? that's a one way ticket to an injury, sir. here stretch with m really quick, just keep your eyes on me and do what I do."

You raise your arms above your head. He doesn't do what you do, he stares.

"Aren't you going to stretch too?" you ask

He stammers for a second before mirroring you. You blush a little, knowing he is getting a full view of your breasts. Then you lean to the sides. After those couple stretches you drop you arms to your side and 'notice' your breasts are out. Feigning ignorance, you apologize and cover them back up.

"Maybe I will face the other way, still follow along though." You say as you turn around.

You bend forward and touch your toes, You glance between your legs and see he is not doing the same. You repeat a few times, holding the bent over position longer than needed. When you finish, you turn around to face him. Pretending you forgot about your top issue, you put your hands behind your head and ask him how it was. He stammers a bit and keeps his hands over his crotch.

"Is everything okay?" You ask

"Yeah, I g-gotta go now though, nice meeting you."

He hurries off. You finish your walk.