This video knitting tutorial will help you knit the slip, knit two, pass double decrease (sk2p). This technique is used to decrease two stitches at once and has a similar look to the slip knit pass decrease (skp).
Step 1: Work pattern to one stitch before where you want to decrease and slip the next stitch off the main needle.
Step 2: Knit the next two stitches together.
Step 3: Pass the slipped stitch over the knit two together stitch.