The reason you are not cumming is probably anxiety, anticipation, or lack of mental focus. I know I have had the same problem, but once i got past being uncomfteable I can cum eventually.
As for the lube, heres what I highly suggest!!!
http://www.kamasutra.com/products.php?cat_id=33
These oils taste so damn good, and work very well. Although, they also have tasty lubes to offer as well as many other things

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