Similar and different.
For a girl the whole world know how big or how small they are. For a boy it is a much more select group. Plus breasts are used to attract the male. Once the female learns the males size they are already pretty close to sealing the deal.
But also the male's size does have a greater impact on the female's pleasure than the female size does on the male's.
I am strictly talking about self esteem issues. There are many men who fear that they are too small and women will not want them once they realize the size, just as many women fear men would reject them for having too small of breasts.
It has nothing to do with overall pleasuring of others but the ability to be comfortable enough in your own skin to become intimate with another person.
Author