I think it happened to me the first time I tried to shave with a str8. Immediately I went to this forum and found an advice to use my wrist, not just my arm to glade a blade. That took some practice, may be 2 more shaves and now I do not even understand how it is possible. Assuming that your angle is correct and the razor is sharp - try to use your wrist more and may be find a slightly different angle to your whiskers for the first pass.