Since you said Touch, I'm guessing we're dealing with a phone.  What phone?  Or what device/operating system?

If I'm right on the phone guess, on mine (Android) I have to do a long press with my finger to get the paste option to come up.  The paste option only shows up if I successfully copied something first, and if where I want to paste it is a valid location.  For example, can't paste a picture into a plain text box.