I'm currently in my 19th week of a 20 week Test-C/EQ Cycle. Earlier in this cycle (about 6-10 weeks in) I barely took any rest days, but it eventually caught up with my central nervous system and now I'm back to a 5 day routine.
At the peak of my "invincibility" I had a long heavy squat workout one morning, went home and took a nap, and returned early evening to do a heavy chest workout. The gym owner gave me that look like "I'm not stupid, I know what you're up to!" I'd go with it while you can though, and when it gets to be too much, take a day or 2 off, or cardio-only days if you can't sit still. Sometimes it really sucks not exercising at all the whole day while on a cycle, especially if you have a non-physical job.