No tips on the panties - but if I were you I would miss at least two classes with her (during the "it" period) as if you were to go there:
(a) all male owners would murder you for making their dogs go C-R-A-Z-Y (even after the class, refuse food at home, howl the nights etc). Especially if you're still in the beginners or puppy classes. If you are in the advanced classes, don't worry about it as the males should be under control and should be taught to obey even in the presence of a female in heat. (plus if you're indoors all the dogs in the following classes will still smell your dog's presence, and you'll "ruin" it for them too). It IS important for males to learn how to behave when there is a girl in heat closeby, but bringing one during the "it"-period to a beginner's class is NOT the right way. At the start of the heat (1st week) and after the 3rd week she'll still smell of heat, but the smell won't be as overwhelming as between 1-3 weeks.
(b) most likely your girl is NOT going to obey you like she normally would, but she'll be very hormonal. Trying to get her to work when she's NOT up for it will only hinder your process as she'll learn to misbehave in class. It's better to not even get her in the situation where she either doesn't want to behave or when she's not paying attention to you like she normally would (at least not until she is old enough and you have the authority (in her eyes) to MAKE HER DO IT even when she doesn't want to).
Not saying that you shouldn't train at home! YES, continue training at home during her heat, but you might need to keep the training sessions shorter than usual, and you might need to take a few steps back during the heat. (eg. when you would normally do an off-leash down stay of 2 minutes at 10 meters, you might need to keep her on a leash, only do 1 minute at 5 meters). Just so that she doesn't get the idea into her head of being able to do something wrong.