You're knitting three stitches into the stitch. Knit into the stitch as normal, but don't slide it off, knit into the back loop and again don't slide it off, and then again into the front loop and slide it off. You'll have 3 stitches instead of one.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry