Commonly noticed among milk fetishists, the addition of real milk (for best results use whole milk) or cream speeds the process.
Churning the cream brings its fat globules together and causes them to clump into lumps of crotchbutter, leaving a liquid called crotch milk.
Generally an acquired taste, as it is a bit tangier than the common grocery store variety. However, some people actually enjoy the taste of properly churned crotchbutter the first time.
Also possible to make chocolate crotchbutter, and chocolate crotchmilk by repeating the process in the anus. Only the truly hardcore appreciate the taste of this 'delicacy'.
Can be used for revenge purposes.
"I went out to her car with my underwear, and smeared crotchbutter all over the steering wheel. She'll be wondering what the smell is for weeks."