Off topic response to off topic post: This is some of the stupidest bullshit I've read on this site outside of the politics forum, especially if serious.
The penis isn't designed to scoop out sperm. You know why that's stupid bullshit? Because: foreskin. Foreskin and its glide mechanism keeps moisture (and sperm) inside the vagina. Circumcision and mutilated penises that scoop out bodily fluids are not evolution because they're not natural; not designed by nature, and surgical amputations do not spark evolutionary change, so there goes your utterly ridiculous theory.
http://www.cirp.org/pages/anat/
"During intercourse the loose skin of the intact penis slides up and down the shaft of the penis, stimulating the glans and the sensitive erogenous receptors of the foreskin itself. On the outstroke the glans is partially or completely engulfed by the foreskin. This is known as the `gliding mechanism.'
The gliding mechanism is Nature's intended mechanism of intercourse. As such, it contributes greatly to sexual pleasure. Also, since more of the loose skin of the penis remains inside the vagina,
the woman's natural lubrication is not drawn out to evaporate to a great extent, which makes sex easier without using artificial lubricants."
http://sexasnatureintendedit.com/eBook/Chapter_05_The_Gliding_Mechanism.pdf
"Importantly, during natural intercourse, lubricating fluids tend to remain inside the vagina, because when the loose shaftskin of the penis bunches up on the outward stroke, it creates a seal that holds fluids in."
Now back on topic...
Notthe7, a different take on guys wondering if they're "big enough", I'd say it may not be a matter of being concerned about being big enough to please, but maybe there'd be a problem if they think you might be the type to keep looking for the next big thing. I guess in the course of a conversation if monogamy is brought up, that issue could be dealt with, but if it's not and you're coming across as a nympho just looking for big johnsons, and the guy is looking for a loyal companion while the lady is prioritizing schlong size, well there's another reason it could be off-putting.