Check out the xset command with the m switch. Here is what the man pages say about the m switch:
m The m option controls the mouse parameters. The parameters for
the mouse are ‘acceleration’ and ‘threshold’. The acceleration
can be specified as an integer, or as a simple fraction. The
mouse, or whatever pointer the machine is connected to, will go
‘acceleration’ times as fast when it travels more than ‘thresh‐
old’ pixels in a short time. This way, the mouse can be used
for precise alignment when it is moved slowly, yet it can be
set to travel across the screen in a flick of the wrist when
desired. One or both parameters for the m option can be omit‐
ted, but if only one is given, it will be interpreted as the
acceleration. If no parameters or the flag ’default’ is used,
the system defaults will be set.
maybe try something like:
xset m 5 10
This gives the mouse an acceleration of 5 with 10 as its threshold. You'll probably have to experiment with it a bit to get it to how you want.