We've all been there: you're dying for a rest but now is not the time to stop. This usually happens either right before or during a show run. Students (especially advanced ones) are very susceptible to this because shows so often align with end-of-term school demands. We can't stop having class in these times but there are ways to help classes be more recuperative.
Vary the movement qualities. Teachers often use class time to refine and reinforce elements that students will use on stage--which is great--but there can be too much of a good thing. If 80% of a dancer's movement is the same quality (flowing/adagio if you're preparing Swan Lake, for example) you are using the same muscles the same way over and over without allowing for recovery time. Aim to have classes that are very balanced. One way to do this is to consider how you would describe the movements in each exercise (without using ballet vocabulary!) and see how many different words come up. The goal is to have lots of words!
Replace some jumps with relevés. You still need to be jumping some (see "variety" above) but relevés are a little easier on the body. Pirouettes naturally incorporate relevés so if you're worried you'll get carried away and give too many jumps, switch your focus and give a turning day.
Guided meditations can be useful in helping students rest. I particularly like to use meditations based on Constructive Rest. Napping is great but students will do that at home (after they do all that homework) so I try to offer something helpful/healthful that they wouldn't be doing otherwise. But I don't do this several days in a row or even for every show. I prefer to keep my classes movement-oriented and save this for when I think it will be most impactful.
Don't be surprised or offended if someone falls asleep during a constructive rest meditation. It just means that what they needed the very most in that moment was REM-style rest.
Learning to be a dancer includes learning how to care for your body without stopping (unless injured or ill, of course). Like everything in life, sometimes the key to resilience during a hard time is through small changes while still working towards the big goal.