Comes from the name of the now infamous med student from North Yorkshire who was known for willingly leaving skid marks on women while having sexual intercourse with them.
Commonly used in a more abstract way to describe a betrayal of trust - the trust of women by men in particular.
Fwths is someone that has a gf but his bff likes him and he CANT FUCKIN UNDERSTAND ITT. So he is "Little Things" (1d song) humanied and he is cute af. He can snob his bff a lot but when they talk she fslls more in luv with him