The penis consists of three chambers, two of them are called the Corpora Cavernosa as shown on the diagram, and the third is the Corpus Spongisum. The Corpus Spongisum is primarily used for urinating and ejaculation. When a person gets sexually excited the brain releases a hormone which sends blood to your penis, filling the tissue within the Corpora Cavernosa to its maximum level. The maximum your erectile tissue can fill with blood creates the size your erect penis presently is. Therefore your penis is in fact allot smaller than it could be if the erectile tissue chambers were larger i.e. holding more blood. Penis Enlargement Pills work by increasing the size of these chambers both in length and width enabling them to hold more blood. This leads to the increased inches in length. Additionally Penis Enlargement Pills allow the stretching of the fibrous sheets (fascia) surrounding the chambers which allows for greater blood flow.