Ok so I've noticed lately that when I don't hit vtec for a day or so I get a rather large cloud out my exhaust. It seems to do it less and less each time I hit vtec on a drive, I'd say I hit vtec a good 10 times tonight and the last time I hit it, I really didn't see anything. I only notice it at night, due to the cars headlights behind me. During the day I can't see anything. I don't notice an oil loss, I check my oil atleast every other day.

Could it just be a carbon build up / rich mixture? Or possibly condensation in my exhaust?