With a Tuff luff, chances are you have a laminate sail... if you don't and have a tuff luff, with a dacron (I do)...
You have to keep the genoa sheeted, drop the whole sail, remove from tuff luff, and secure halyard.
now it gets messy especially under way, but here goes...
you have to scramble fore and aft folding the sail as you go up... when you get about halfway up, you can fold standing OVER the sail... it's a PITA... I've not found a better way though. Then roll it and stuff it.
Here's the one that eludes me the most... TUFF LUFF with laminate sails (requires rolling either from head to foot, or foot to head). There is generally not enough space to roll it ON deck of my boat, at least when I've tried it's crinkled and generally left me with a mess. I've tried to secure the foot, and the clew, and remove and secure halyard, and leave sheeted and rolled from head to foot, but about 1/3 the way in, the tootsie roll, collapses and makes it impossible to continue. The ONLY successful way to roll a laminate sail I've found is 2 people doing it as described while under way, or better 1 or 2 doing it once back at the dock and flat ground can be employed (it's also the only way I've found to get the package small enough to fit back into the original sail bag, that is long and slim, generally the length of the foot). I'd love to hear how racers handle that. Best I can tell if you have to change gears mid-race (with a dual-headfoil rig) the crew rolls it "roughly" and stows it below. The new headsail goes on and up, before the old one comes down. It helps to have soft shackles or individual sheets for each headsail to do "under way" sail changes like that though. Again, I'd like to hear what others do especially short handed.