Oct 23, 8 Penis-Friendly Foods to Boost T-Levels, Sperm Count, and More. (Erectile dysfunction in younger men is rising and about 1 in 9 men will develop prostate cancer in their lifetime.) Caffeine is shownTrusted Source to improve blood flow by relaxing penile arteries and muscles. During an erection, the arteries expand to increase blood flow to the penis. The blood fills two tubes of spongy tissue in the penis (corpus cavernosa). When you're at work, hitting the gym, or running errands, the arteries supplying blood to your penis are only partially open. This provides the blood flow needed.