Duff, on the Food Channel show “Spring Baking Championship”, said this one when describing a contestant’s ice cream. Based on the context, I think it’s a mash up of “skirting around” (to avoid someone or something) and “crossing the line” (to change from being acceptable to being unacceptable). Perhaps he was thinking of “skating on thin ice” and pulled the word “skirt” instead of “skate” from his brain. Any other thoughts out there in malaphorland? A big thanks to Brenda Hubbard for hearing this one and passing it on.