I don't really see how .xinitrc is relevant here. That file is read by xinit, an old way of starting an X session and one you are almost certainly not using. In most modern Linux systems, the X session is started by a login manager service, for example lightdm or gdm2 or whatever and not by xinit.
Anyway, according to the LXDE wiki, you need to add these lines to $HOME/.config/lxsession/<profile>/autostart. Change <profile> to whatever you have in $HOME/config/lxsession. Just edit (or create of it does not exist) the file and add the relevant lines to it:
xinput --set-prop "Razer Razer DeathAdder" "Device Accel Constant Deceleration" 4
xinput --set-prop "Razer Razer DeathAdder" "Device Accel Velocity Scaling" 1
.xinitrc. – Skippy le Grand Gourou Oct 26 '13 at 22:03.xinitrcbe read unlessxinitis used to start X? – terdon Oct 27 '13 at 15:17startxin my.bash_profile) so other people might as well… Besides, it has never been clear to me where to put such commands as well as it's different on almost every setup, hence the suggestion. – Skippy le Grand Gourou Oct 27 '13 at 16:47