(Dedicated to 2nice, because he asked so nicely )

Any guy who has awoken with morning wood and a full bladder knows that aiming your boner so as not to make a mess of the bathroom floor can be a bitch. A solid erection just never wants to bend enough (or in the right direction)to be cooperative. This is because Nature intended that boner for SEX and not for URINATION--and MALE ANATOMY is designed with that separation of functions in its blueprint.

Struggling to aim that morning stream aside, it can also be a bit tougher to get the pee flow going while sporting an erection than it usually is when your dick is flaccid. For most men, it is POSSIBLE to pee while hard, it just takes a little bit of focus and willpower. Some guys can't piss at all until their hard-on subsides. In either case, that is also by design.

As I have mentioned in other posts, the male URETHRA, a narrow tube which passes from the base of the URINARY BLADDER to the tip of the GLANS PENIS (where it ends at the MEATUS--the pee slit)serves the dual role of being the passage which allows both SEMEN and URINE to leave the man's body.

URINE, being acidic, is deadly to SPERM, so the shared system is set up to keep the two fluids from sharing the passage at the same time. (There are also two sets of glands in the male REPRODUCTIVE SYSTEM--the SEMINAL VESICLES and the COWPER'S GLANDS--which provide an alkaline fluid to SEMEN to neutralize acidity in the URETHRA.) This is accomplished by a pair of SPHINCTER MUSCLES--one internal and the other external of the BLADDER--which stop URINE from flowing.

The EXTERNAL SPHINCTER, located at the base of the BLADDER and the top of the URETHRA is the one that has the mundane task of keeping you from peeing down your leg as soon as URINE is produced by the KIDNEYS. When it is closed, you are "holding your water". It restricts the flow until you voluntarily relax it so that you can piss.

The INTERIOR SPHINCTER MUSCLE, also at the base of the URINARY BLADDER, just at the internal opening of the URETHRA, clamps shut of its own accord as soon as a guy gets an ERECTION. Its function is to keep SEMEN from backwashing into the BLADDER during ORGASM and EJACULATION and to serve as an additional safeguard against URINE mixing in with the SEMEN as it leaves the PENIS.

Because it is designed to stay shut until EJACULATION has happened and your ERECTION has subsided, it takes a bit of thought and focus to get it to relax against its programming--which is why it is harder to PEE with a BONER.

You're welcome,
Will