Stick to your lighter days. This just makes sense. If you know that days 3-5 are lighter than days 1 and 2, just keep your panties on for that 48 hours. Let the anticipation build and avoid any awkward trips to the laundromat.
If it doesn't bother your partner and they're totally down for day 1 sex, evaluate your concerns. Maybe it's something you could get over -- after all, it's no less sanitary than what you've been doing. It's just a bit redder!