One of the quickest (and most useful) toys you can make yourself is a spreader-bar. Ten minutes at Home Depot, five minutes with a drill.

Simple dowel wood; get something heavy, maybe 3/4". Two ringbolts through holes you drill about an inch in from the end, to prevent cracking. Nuts put onto the bolts with ThreadLok or the like, so they don't unscrew. Make several in different lengths, as they are doggone handy.

Practice items for whips and such can be a length of garden hose, a length of heavy power cord (such as would be for an iron or vacuum), or even a length of wash-line or curtain pull-cord. Those will help you develop accuracy while working somewhere inconspicuous, like in your basement or such.

The actual making of whips can be VERY fussy work; there are a lot of pages on the web referring to this, such as http://genvieve.net/sca/whipcording-howto.html
http://www.juggling.org/~conway/video/snake.html
http://youtube.com/watch?v=5sZq0LmVdAc
http://www.instructables.com/id/CR-V...e-A-Bull-Whip/
http://www.davidmorgan.com/whipfaqs.html

All these are great references I have used, especially the second above.
CAUTION: THESE ARE ****NOT**** THE TOYS YOU WILL FIND IN NEIGHBORHOOD ADULT SEX SHOPS. These whips are serious business, not for the inexperienced. WHIPS CAN KILL OR MAIM. The old thing about putting your eye out Mom used to say? Right. Or worse, your partner's.

Play safe and sane!