Metal Gear Solid 2: Substance

Snake and his Snake

By that_guy_beta | 2003-08-24 | Konami

1: Goto the locker rooms in the tanker mission and open up the lockers until you find the poster with a girl wearing only a black bikini (I think its the northwestern one)
2: Stand fairly close to the picture and make sure you can see nearly the whole thing while in first person view
3: Wait 15-20 seconds
4: Call otacon on your codec
5: I guess snake does get lonely some times :P

You have to stand in the almost perfect position and look at the exact area.