During ovulation, many women do produce much larger amounts
of the natural secretions, some to the point of its running down their legs. Women who practice the rhythm method of birth control use this as a gauge to help them verify their cycle. If a woman is lucky enough to be very regular and also has these signs, (plus a husband with good self control) rhythm works.
The added moisture makes it fun to try other things in that warm very wet area since the partner can't try it.