I've heard of no specific time to drink black sesame seed tea. I've had it at just any every time I can think of. I didn't notice any different effects.
I haven't been consistent enough to attribute any effects to the tea. I'm not a coffee or tea drinker so I find drinking the black sesame tea calming and filling. A is the result of the warm liquid, like Yin Yang water, but eating all those seeds has a noticeable effect on my stomach.
My advice is drink it whenever you like. If you want to use is to surplant and cafiene habit or replace a snack or just because you want a little more kidney energy, then I think that is great. Just do it for yourself.
You are perfection.
Iam2