Tricycles are fun if you can find one to properly fit your partner.

You can tie your partner with her knees on the back footrest, stomach
on the seat and hands attached to the foot pedals.  In this position she
can drive the tricycle around while you do various things to her or give
her various assignments.

For extra fun you could attach clamps to her breasts/nipples/labia and
then run a string to the pedal so as she moves the pedal she tugs on
her wabbly bits.

She could peddle around a room so everyone can spank her butt.

If you are into fireplay you can have her wear several layers of cotton
panties and/or jeans, light the seat and have her have to fetch the paddle
and bring it to you to get her burning butt put out with the paddle.

Lots more options and things you can do with her in this position.