Everything is okay to do. It depends on your goals, and how fast you want to gain in length versus. girth.
2 sessions of lengthwork are better according to my experiences. You want maximum amount of temporary elongation, and then keep that elongated throughout the day. Doing a second session after work is the way to go about it, you get double temporary elongation and that's better then one.
I recommend you to watch these videos, there you have everything explained.
FAQ's with DLD (doublelongdaddy).
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