...that's where I'd draw the line. If she needs me to swim in the red river to help ease her cramps a little, I'd probably do it on the condition that I get to sport warpaint like a warrior about to plunge into the thick of battle. Drinking from it... no thank you.
In college, I saw one of my friends after he'd drank from the red river and he looked like something out of a horror movie; his beard was all gory looking. It took me years to unsee that.
EDIT: But lemme tell you, tampons can be a punk or metal musician's best friend (along with duct tape.) Why you ask? Moshpits. This one dude told me a story where this guy took a massive elbow to the face and this girl shoved two of her tampons up his nostrils.
EDIT 2: My 3rd choice superpower would either be accelerated healing or "oculus reparo" to magically fix eyeglasses like Hermione does in Harry Potter. Why? Moshpits again.