If you are having trouble getting your right hand needle under two sts to decrease, then you probably have a tension issue. The 2 sts on your left needle are tight, because you knit them tightly, making it difficult to get your right hand needle under the two sts. Work on losinging up your knitting a little and that should help. Till then you'll have to go slowly and muddle through. HaHa. Or try, using a smaller needle just to get the needle under the 2 sts and pull the loop through, but then you have to put that loop on the original needle or your knitting/guage will get even smaller. Yikes!