All mugs are different shapes and sizes, they are all very unique therefore no mug cosy is going to be the same size. I will give my exact stitches and try to explain in brackets how to make the cosy fit whatever mug is being used.
For mine I used a 5mm hook however I crochet tightly so a 4mm hook is probably better. I also used DK/8ply yarn in yellow, blue, a little bit of grey and a little bit of black.
Abbreviations:
SC - Single Crochet
SS - Slip Stitch
In blue chain 44 and join. (chain as many as needed to fit the mug comfortably, not too loose)
Round 1: SC in each chain around, join with SS to first SC
Round 2: SC in each stitch around, join with SS to first SC (if the first row it a bit too loose or tight then increase or decrease as needed in this row)
Change to yellow yarn
Row 3: SC in next 40 stitches, turn. (Crochet as many stitches as needed to leave a gap big enough for the mug handle)
Row 7: SC in each stitch. At end of row chain 30, turn
Row 8: SC in each stitches.
Finish off.
You should end up with a tail like this:
Make a loop with the tail by sewing the end just underneath the beginning of the tail.
Place the cosy on the mug to find a suitable position for the button. Sew the button on.
Eye Strap
Using black yarn surface crochet a straight line about a third of the way down the cosy. Find out how to surface crochet Here. It's easy and once learned there are so many possibilities!
Eye
Using black yarn chain 2
Round 1: 5 SC's in the first chain - 5 stitches
Change to white yarn.
Round 2: 2 SC in each stitch around - 10 stitches
Round 3: (SC in next stitch, 2 SC in next stitch) around - 15 stitches
Change to grey yarn
Round 4: (SC in next 2 stitches, 2 SC in next stitch) around - 20 stitches
Round 5: (SC in the next 3 stitches, 2 SC in the next stitch) around - 25 stitches
Finish off.
Sew the eye on in the centre of the mug with the Eye Strap running through the middle as in the picture.
Mouth
With black yarn surface crochet a line under the eye as in the picture above.
And that's it! Here are the four I've made for gifts:
(The one on the right is the Original and a different sized mug hence why it looks different to the others)