Semen is the fluid that leaves the penis at ejaculation. Sperm are only a small part of it. Prostate and seminal vesicle secretions make up most of the volume. Color is usually off-white. A sudden red or brown stain is a reason to call a clinic.

It can carry infections. It can start a pregnancy if it meets an egg on the right week. Withdrawal is a weak plan against either. Taste and smell vary with diet and are not a reliable health report, despite a lot of folklore.

Dried semen on fabric sets. Rinse in cold water first if you care about the sheet. If conception is the goal, timing around ovulation matters more than folklore about positions after.