Try this:
http://www.meltybread.com/forums/kohaku's-video-room/nicovideo-account-tutorial/
Also, because I like getting people's hopes up, Disgaea 4 for the PS3 is incorporating a punishment system that will have tickling.
In the pic below, the options are:
Beat with a wad of money
Make her sign documents
Tie hands
Tie feet
Talk about ecchi things
Make her say compliments
Make her give a massage
Listen to her worries
When you tie her hands, the punishment (as read on the bottom of the pic) is: "Tie hands and tickle armpits"
Logically, the tie feet command would be something like "Tie feet and tickle soles," but there's no confirmation of this yet. The game comes out Feb 24th in Japan, so we'll know more by then.