Stoffet cGMP produceres i penis ved seksuel stimulering og medfører en afslapning af musklerne i svulmelegemet (corpora cavernosa), hvorved blodstrømningen til corpora øges og der således fremkaldes en erektion.
During normal sexual stimulation, cGMP is produced in the penis, where it causes the muscle in the spongy tissue of the penis (the corpora cavernosa) to relax, allowing the blood to flow into the corpora, producing the erection.