I did a Deca only cycle years ago before even going on this board and could not understand why my dick fealt like it became a vagina, in otherwords useless. It really freaked me out and it was inexplicable to me at the time. The second time i ren it alone, the reverse happened. My sex drive went through the roof, go figure. Did some adaptation take place? Maybe.
Also of note that the only deca i used were a mix of Organon Yellow tops and Greek extraboline which i brought back personally from those countries. It was all VERY legit high quality stuff. But the first time deca dick, extreme facial bloat of all deca cycles left me willing to do without it. Oh, yeah, also the recovery period took 6 months easy, even with PCT. I just have had no sex drive afterwords for a long time no matter what i did. Using it with test IMO masks it's tendencies.