It pulls air in through the ports on the side and the keyboard at quite an impressive rate. If you hold a bit of tissue paper to the ports on the side while the fans are going you can see it being pulled in. I think it also draws air in from the keyboard too.
Asus ROG G751JT-T7115H
17.3" IPS, Intel i7-4720HQ, 16Gb RAM, NVidia GeForce GTX970m, 256Gb M.2 SSD + 1Tb SSHD