Make a seal around the. mouthpiece with your lips. • If using a mask, place it over your mouth and nose. You will see a fine mist when the treatment is started. Relax. and breathe normally. Every 4 to 5 breaths, take a deep. breath and hold it a few seconds. Then exhale completely. Continue until no mist is present. Tap the nebulizer cup at times to be sure all the medicine is. nebulized. The treatment will last about 10 to 20 minutes. Remember to cough and bring up loose mucus at the end of. your treatment. Nebulizer Treatments. You may receive medicine through. a nebulizer treatment, also called. a breathing treatment or aerosol. treatment.