This is how this went:
Home Despot Guy: Can I help you find something?
Q: A good all-weather heat-resistant silicone caulk.
HDG: This one might be good for that. Doing a sauna or hot tub?
Q: Nope, trunk leak.
And now my trunk doesn't leak. Furthermore, having recommended it to my coworker, hers doesn't either.
You gotta problem? Yo, I'll solve it.