If stimulation continues, a man will enter the plateau phase, which varies in length, depending on the type of stimulation and his own desires. (Many individuals like to prolong this phase with extended "foreplay.") As arousal levels rise, blood pressure, heart rate, respiratory rate and muscle tension also increase.

Increased blood flow further enlarges the penis and causes the testicles to swell to approximately 50 percent beyond their normal size. The prostate gland becomes larger. The tiny Cowper's or Bulbourtheral glands release a few drops of pre-ejaculatory fluid, a clear, slippery substance which is secreted from the tip of the penis. Note: pre-ejaculate may also contain some live sperm from a previous ejaculation and can get a woman pregnant. Many men also develop a sex flush (redness of skin), predominantly on the chest.