hmmmm ... from my point of view .. play safe

safe period
-4-5 days before menstruation
-4-5 days after menst

or

check the consistency of the secretion by placing the secretions between thumbs and index finger then try to  strech it
= if the secretion is thick,mucoid type,sticky and non elastic then can consider as safe period as well

= if its very thin,watery and very elastic = ovulation period

what is ovulation period ??
means the ovum or egg is being release on that day,sex appeal is definitely higher -as we all kw the main aim to have sex is to have children .. but its consider unsafe period if u dont wanna conceive