I thought I posted this but I can't find where I did it so I'll post it again. My brain is not working on all cylinders I think.
I downloaded a free earflap hat pattern from http://www.jananas.com/basic-ear-flap-hat-knitting-pattern/.
She has the greatest method of adding the earflaps and not getting those nasty little holes where you've done the add on, plus it also works for when you are joining in the round. Rather than try to explain it in my wordy gobbledygook I'll cut and paste
With the ear flap on the circular needle, cast on 22 (24, 26) stitches using a cable cast on.
Join and knit along the remaining ear flap, making sure that the remaining ear flap is oriented so that you knit along the right side of the piece (i.e. you’re not knitting across the purled side). Use the tail of yarn from the ear flap to knit the next 4-5 stitches to help the join. Continue and cast on 18 (20, 22) stitches. Total stitches on needles before joining: 76 (84, 92). Now comes the neat part
Transfer last cast on stitch to the left hand needle and k2tog to join in the round, making sure that stitches aren’t twisted. Total stitches at end of round: 75 (83, 91).
Next Round: Knit across ear flap, k2tog at small gap that was created by the cable cast on. Repeat at the start and finish of the next ear flap, for a total of three decreases. By doing this, the join at the ear flaps and across the remainder of the brim are stronger. Total stitches at end of round: 72 (80, 88).
And voila - no holes!! It's the neatest thing ever and would work with almost anything where you area adding pieces in and picking up stitches. Now, to post, and not lose this again.