We each took 200mg MBDB and went to a nature preserve. The effects were noticed in about 30 minutes. The up ramp was significant, taking from 30 minutes to an hour to achieve a +2.5 for myself and a +3 for my partner. We had to sit down due to the profound feeling of intoxication. It was difficult to come to any conclusions about anything or engage in rational closure of ideas, but that was OK. For the next 3 hours we sat in an old orchard on a perfect summer day mostly with eyes closed and in relative stillness.
When I tried to stand up I would feel tired and go back to the ground and lay down. The feeling of lethargy was quite extreme, and I thought I might fall asleep on several occasions. There was one moment of tremendous pressure at the peak, but an absence of the insight one would usually associate with similar compounds such as MDMA. I would not say it was a waste of time but it was difficult to integrate. Closed-eye visuals appeared later as with MDA. Very slow down ramp lasting another day before the feelings of lethargy and confusion vanished.