Yes you certainly can :)
If you're big-breasted and get sweaty under your breasts or suffer from heat rash then Woohoo is perfect for you. Apply under your breasts just the same way you do under your arms.
You'll find it helps big-time with chafing and rubbing too.
If you suffer from smelly feet you can apply the Woohoo on your feet just the same as you would under your arms. Please remember that it might make the soles of your feet a little slippery (as a benefit it can help stop rubbing/chafing!) so don't dive into your thongs and hit the dance floor right after applying. If your feet are always excessively sweaty, it might be a good idea to talk to your medical professional as they might be able to help.