Yea i tend to be able to do this also, but not to an extreme extent. Your not gonna diet down and blow up at the same time. Best iv done is this time around. 224lbs 15% 6 weeks down to 212 7-8% (behind schedule a lil 6 weeks out). If your bodyfat is higher to start out with, i believe you can probably do this to a greater extent. Kevin Levrone is known to bulk to a contest 40lbs, but he also takes 6 months off lifting completly after shows, so a lot of it is muscle memory.
I dont do nothing special that you dont see others do. Low intensity cardio 38-45min 4-5 days a week at 3.0 speed 4.0 incline treadmill. Arrange the majority of my carbs around workouts and to support muscle recovery. Il eat breakfast after my cardio (like 5 egg whites 2 whole + whole wheat + oatmeal) then 2hrs preworkout shake go to gym then have a post workout shake. Solid food meal 1hr later, then solid food meal 2hrs after that and thats it for carbs for the day for carb meals. Cut carbs around 5hrs before bed.
Pickles is right, diet most important, but you gotta figure out what works for you. Iv tried 4 different diet strategies and this one is the one that seems to work best for me. Have to also know how to adjust kcals as body composition changes also to keep progress moving