I've been using an electric toothbrush with the brush-head removed the last week or so on about 90 plants / 20 diff varieties. This seemed to be as close to the vibration produced by a bumblebee as possible from all the recommendations I read about (and probably releases the pollen the best based on the visual feedback of seeing the little clouds of pollen drop when you touch the vibrating head to the behind the base of the flower slightly down the stem -- I wouldn't touch the yellow part).

Absent that, just a little shake, a gentle flick or anything that gives the flowerhead a little movement (rotating fans)?

The excessive heat and humidity is probably stressing certain tomatoes not built for it -- so you could be pollinating well, but still have blossoms dropping out due to stress.

Jury is out on how well its working for me -- my flowers just started coming out last week, don't seem much development of fruit yet.

I have an old brush head from my sonicare tooth brush. Turn it on and touch the outer side of the tomato bloom where the petals and sepals join. In good lighting , you can actually see the pollen pouring off the flower. It cant be too humid,the pollen are stuck in clumps or too dry ( the pollen wont stick where they are supposed to). electric toothbrush works beautifully!!

You may already know, but I won't make assumptions. Tomato flowers can pollinate themselves. You don't have to transfer pollen from one flowere to another. Shaking or vibrating causes the pollen to drop onto the receptors in that flower.
Jim

Agree with Jim and you also need to remember that given high heat and high humidity you can vibrate them to death with whatever you want - toothbrushes included - and it won't make a darn bit of difference because the pollen isn't viable.

Dave