during ovulation your discharge will look like egg whites actually, sometimes there's quite a bit! I've also had it yellowish (like mucus when a kid has a cold or something!), but nothing was wrong (I happened to have my routine pap at that time and there was nothing wrong), sometimes yellow means infection, sometimes the discharge is like cottage cheese (infection too), and if it smells really bad? (infection). The mucus is there around ovulation so that it can carry the sperm upward easily... that is when you are the most fertile. You'll notice that about a week before your period you'll be "dry".