ROTFLMAO!!
ErikaXO has got it right - it has to be the right size and he has to know what to do with it (it ain't just "insert tab A into slot B
).
I think the Kama Sutra says something about men having one of 3 sizes and women having one of 3 sizes (deer, elephant, something or other) - and it's best when the man and woman are the same relative size. Put a big man and a small woman together and the woman will be in pain; put a small man and a big woman together and neither of them will feel anything.
But even if things are matched pretty evenly, he's got to know how to treat a woman - size and technique are both important.