With the latter, it is often manifest as spots of blood on the underwear, pajamas or bed sheets.. Irritation of the gland (
prostatitis) can also cause it to become inflamed and predisposed to bleed. Some factors leading to inflammation include too frequent or too infrequent ejaculation, sexual arousal without ejaculation, withdraw at the time of ejaculation, excessive alcohol or spicy foods, prolonged sitting or bike riding, etc.