Tedd is the worst at playing doctor. Grace can say all the suggestive stuff she wants, and Tedd will just give an actual amateur physical.

Okay, that's not completely accurate. The real danger would be accidentally coming up with symptoms that Tedd would find fascinating on a scientific level. That's easier than it sounds, because all it really takes is Tedd wondering how such a condition would actually work, and suddenly Tedd will start working on a hypothesis.