IIRC usually the diode is at a right angle to the lens. That being said, you are messing with something that could quite possibly damage your eyesight etc. The "safe" limit for laser diodes is usually around 5mW or so. These run at MINIMUM, ONE HUNDRED milliwatts with some running as high as FOUR HUNDRED milliwatts
. That is EASILY enough power to damage your eyes (either directly or via reflection off of a wall). DOn't forget you don't have to be looking at it to damage your eyes. It can easily damage the non-focal portion as well (seeing it out of the corner of your eye). Honestly, unless you know what you are doing (ie have worked with lasers before, know how to implement safety precautions, etc.) I would avoid it. It's like giving a child a loaded shotgun, something is bound to go wrong. I haev read of people on the candlepower forums accidentally blasting their eye with 30mW or 50mW laser diodes while cleaning and causing PERMANENT damage.
At minimum get yourself some filtering goggles for use at 650nm (DVD burner diode wavelength).