I've never run deca without test but there are those that do an never face "deca dick".... everyone's different. I usually don't have that problem as long as I have a decent amount of test in the mix.... add some proviron and you're rocketing through!
I had no problem with deca dick when I did stack it with test. Although it did take longer to get a nut never was a big issue. My girl was pleased that I wanted to fuck all the time from the test and couldnt have a quickie if I tried.