system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why does it feel so much better when someone else touches rather than you touching yourself?
gpt
When you touch yourself your brain plans the movements required to make the contact. When this movement is planned, 2 copies of this information are sent; one towards the part of the body performing the movements and one is sent to another part of the brain (the efference copy). When the movement has happened, your nerves 'report back' the outcomes of the movement and this is 'compared' to the efference copy, and if they match up then the planned movement has occurred as predicted and it is very difficult to be surprised by the outcomes to that movement. 

Now, if someone else does touches us, then we do not have the predicted outcome and the sensory information is novel and gets a lot more attention and has a greater effect on us.