DIY Eyelash Thickening Serum with Coconut Oil Adding 1 drop of Lemon can further enhance the oil's cleansing and stimulating properties. Adding 1 drop of Lavender will nourish your lashes and follicles. Add the essential oils (EOs), top off with Fractionated Coconut Oil and you're done! Gently coat your lashes with the serum after washing face and removing all traces of eye makeup. Blending and storing your eyelash serum in a 10ml roller bottle will give the Lemon and Lavender good dilution and ease of application!