Thanks for helping me out with this. I read Danny's blog on steeping before starting, but it seems there no consensus. Some people maintain that single flavor liquids don't need much steeping and can be vaped after giving it a good shake
My experience (which is quite limited) with RY4 is that it does take time, and gentle heat helps speed it up. Of course if you are in Cairo, maybe there is plenty of ambient heat to help out a bit. Where I live, the temperature almost never exceeds 75 F, so I carry new mixes around in my pocket to keep them warm. But you can sometimes get the color change started just by setting the bottle in hot tap water, changing the water when it cools down, in about an hour.
[edit] I am pretty new at this, but if I have learned anything so far, some patience is required.
[edit 2] My reading so far has indicated that some flavors develop much more slowly than others, with fruity flavors being the fastest, and
tobacco and vanilla flavors (RY4 is both) taking more time. I do know there is a pre-made RY4 that I like a lot after it has steeped for a week and breathed overnight at least once. But when I first get it (these guys only do made-to-order), it is not very nice at all.