To have sand in one's vagina means to be bothered, annoyed, or angry about something. The vagina in question is a proverbial vagina; people of either gender can have a sandy vagina.
"I have sand is my vagina" is synonymous with "I'm pissed off", "I'm annoyed" etc. Often shortened to "I have sand"
I have sand in my vagina about people asking stupid questions at work.
I have vaginal sand because So'n'so is being a real jerk to me.
That's not cool at all. I have sand about that.
I have a sandy vagina because I missed out on a promotion.