Seriously though naps

My son never used to nap at all i downloaded the huckleberry app and it tells me when to try him for naps weve been doing this over a month now and seems to work. My question is how can i get him to nap on his own he wont nap on me hasnt done since he was 2 weeks old literally he turns into the exorcist as soon as you try and hold him anywhere other than on your hip. I have to rock him in his doona for a good 20-30 minutes for him to have a 25 minute nap if im lucky. Hes great at self soothing at night i put him bed wide awake and within 5 minutes hes sparko x