Answer:
the only amusing part of the body
Better touch me before you proceed to second.
People need me, yet they give me away every day. What am I?
I am not a toy though many use me for pleasure. I have a butt but I cannot poo.
I fly yet I have no wings. I cry yet I have no eyes. Darkness follows me. Lower light I never see.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?