Have you ever tried african threading on your hair? You might remember it from your youth (I certainly do) when perhaps your mum or auntie wrapped huge amounts of thick black thread around sections of your hair to create stiff , sticking out spikes of hair. Well recently I have revisited this method of wrapping my hair- not as a styling option but rather as a way of stretching my hair. It's fast and easy to do and works really well yielding similar results to a light blow out. I would really recommend you give it a try if you're looking for a good way to regularly stretch your hair without using heat. Here's part 1 of my video explaining the process:
Here is part 2 showing the results:
Note: Apologies for the low lighting in the video, I recorded the video late at night!