Your girlfriend and roommate bonded when you went on your weekend fishing trip. You were reeling in an 8 inch trout, while she was taking 8 inches of cock.
The small dick in this pic is mine, and I'm a little over 8 inches, for comparison. We searched forever to find a dick that was bigger and finally we lucked out and found a monster. Wife has a new favorite, and so do I.
The average female skull is 22 cm/8,5 inches in height. Taking that as reference, this cock seems to be in the 25 cm/10 inches range. Colloquially known as a "Great White".