The morning after you wake from a dream you wish to never repeat, immediately strip the bedding and open the bedroom windows to air out the room. If you store any items under your bed, remove them to a new location at least for a few days. As soon as you have time, sweep or vacuum the bedroom with special attention to under the bed, and follow the instructions for Spiritual Cleansing of Bedding.
The next night, dress the white candle with the Peace oil, and shower or bathe with the candle burning nearby. Dab your forehead, wrists and the soles of your feet with more of the Peace oil after emerging. Get ready for bed, and take the burning candle to your bedroom with you. Put it in a safe place to keep burning while you rub the four corners of the bed with Peace oil, and also dab a bit onto your pillows.
Finally, rub your head with a few more drops of the Peace oil. Ideally you should leave the candle to finish burning on its own, but if the candle is burning slowly or you don't feel you can do this safely, blow (don't snuff) the candle in order to demonstrate that you have completed the spell. Go to sleep and dream peaceful dreams. Be sure to ritually dispose of the candle remains the next day.