I strongly agree with others here on the point of subtlety. Tonight's dose of 10mg is my fourth and best experience with this.
The first time was with 10mg + Cannabis and two other friends. We laughed a whole lot at old Dr. Who re-runs and walked to our favorite Chinese restaurant at around hour 4. We felt on the threshold of visuals at this dose and disappointed by the "lack of effects", yet we had much fun that night.
The second time was with 10mg + 45mg 2C-C + Cannabis food at an outdoor event. The synergy was overwhelming with distinct peaks at T+90 (2C-C/Cannabis) and again at T+180 (2C-T-21). The was undesirably strong and negatively influenced by outside circumstances (like a thunderstorm!) The afterimage of a lightning flash persisted for several minutes after the fact.
The third time was with 13-16mg (The dose was measured, I just don't recall it). It was hoped this would bring out the full nature of the material. Unfortunately, it induced intense nausea and chills during the come-up followed by dysphoria, intense feeling of heat, and a "feverish" mental state. As with the 10mg dose, it seemed as though I was at a threshold in which visuals were about to show through, but there was nothing interesting.
So tonight, recognizing that this substance should be enjoyed uniquely in its own right, I tried 10mg with my partner (also with me in the previous experiences). The come up was a bit uncomfortable in that there seemed to be increased attention toward the disagreeable guts and headache that I woke up with. At T+2hours, all of that melted away shifting to a hyper, playful mood. The lady and I made a few batches of cookies together before I could convince her to follow me to the bedroom.

Two hours later at T+5hours the need for food began to overwhelm other urges and food was heartily enjoyed, etc.
I would be especially interested to see how the receptor binding profile of this chemical compares with substances such as 2C-I and maybe 2C-E. This one distinctly reminds me of the body effects of 2C-I except that the mental and visual effects are some how muted. It was certainly more like 2C-I than 2C-T-4 or 2C-T-2 which has recently become a favorite of mine. I also doubt a serotonin releasing component as I did not experience any particular "issues" in the bedroom.

I wonder if the particular effects felt in this compound are mediated by the 5-ht2c receptor? I think 5-ht2c has been associated with, among other things, increase in body temperature and penile erection! The problem with studying this receptor is that it is hard to find agents that effectively discriminate between the 5-ht2a and 5-ht2c receptors, thus psychedelics may exert their effects due to action at both receptors.
Ahh speculation is so much fun...

And I would certainly advice to keep the dose low on this one and appreciate it for what it is. Too much clearly results in dysphoria and potentially worrisome physiological side-effects.