How do they know.

[Toddlerteaplease]

Cheddar will often not puke for weeks. But then the day after I put clean sheets on the bed, she's sick on it. Last night she went one better. She'd caught her claw and there was blood all over my clean bedding. none on the carpet or on the laminate floor. Just on the bed. Arghh!

Not so sure about the claw, but she's obviously waiting until you change the sheets so a) she has somewhere nice to puke and b) she can admire the patterns it makes better on a very clean sheet.