Glopping is slang for menstruation, aka having your period or being on the rag. Women often prefer this to more vulgar terminology because it can be used in public or as an inside joke.
"She is really cranky because she is glopping this week."
derivative usages:
"have a hemogloppin day".
"its Gloptoberfest in my house this week".
"next week is Gloptober".
heavy flow days may be described as "gloptastic"