At the end of the day if you have never heard of sealing your ends this can sound more complicated than it really is, but sealing your ends is simply locking in moisture. Your ends are the oldest part of your hair and naturally when anything ages extra steps are needed to aid in a healthy upkeep. Especially the curlier the hair the more fragile because at every curling point along the strand is a potential point of breakage but also because the sebum from your sebaceous gland has more difficulty traveling down your strands.
Sealing your ends is a process performed after you have moisturized your hair with water and simply coating them with your choice of oils or butter. The oils act as a barrier and hence provide a protective coating to your ends. This means your ends will stay moisturized longer because the moisture won’t be able to find it as easy to escape the wall of oil surrounding it. To seal your ends properly you must saturate your ends with water. Placing 100% moisture onto your ends can only be done by water and water alone. Water can penetrate the hair shaft and reach the cortex. There is only one kind of oil on earth to even mention, that comes close to water at such high percentages and that is Coconut oil. Coconut oil is in a league by itself no other oil even comes close but Olive and Avocado oils at much lower percentages can penetrate the hair shaft as well.
Depending on the porosity level of your hair, some more than others, may need a thicker-based butter or oil to maintain a long lasting seal. This may not be a concern for those who seal more than once a week but for others who only seal weekly, I find a heavier condensed butter or oil such as Castor oil works perfectly for maintaining the moisture within my ends till my next seal treatment. Remember the oil’s job is to protect the moisture (water) that was just absorbed by your cortex. More protection equals longer lasting moisturized ends.