The sub could be tied up and blindfolded. You take a feather which at fist doesn't seem tortureous but it is. That light touch is deliciously tortursome especially if you know their tickleish spots or their hot spots. Just a thought. I personally love it. Kitten
For play however you do it then get a cold drink and drink the ice
Do not let them see you put it in your mouth just finish the drink push her onto the bed and pleasure her . Run yor fingers lightly over sensitive place and kiss all over with the Ice
Eventually take the half melted cube and hold it with your teeth or hand over any sensitive area. let them watch the drop gather and acumulate.
You can fill a condom with water, tie it off, and freeze it for an icy dildo. You can use this anywhere on the body the way you could a regular ice cube but you can also insert it various places, you can always put it in a pussy or ass and just let it melt (with or without removing the condom first if you take the condom off have a towel under them).
Nipple clamps, pussy clamps, weights.
Spanking, flogging, whips.
Tie them up, put a vibrator, and an ass plug (or a vibrating ass plug) and leave them...for however long.
Enema followed by a very tight ass plug before its emptied. (Don't know about other people but I'm fine not getting pictures of this one)
There is a lot really that you can do. With anything, be careful, don't push them farther than they can handle.