Your location is fine, I have had to shove tiny transmitters between actor's legs before because of nudity/tight costuming, so where they are at should be good.
You mention stress on the cables -- do you mean moisture, or is the physical stress of the dancing damaging your cables and shorting the
connector?
While a lot of people are in the "pro-condom" camp for transmitters, I try to never condom my mic packs -- it holds in moisture, and I find damages more costumes than is good. I start with a good, solid, sweat-resistant neoprene pouch to hold my transmitter in. If it's super sweaty I
throw a packet of silica
gel in the bottom, and pad out the pack with a cotton ball on the bottom, back (swisspers), and top. The cotton will hold a lot more sweat in, as opposed to binding it to the transmitter like a condom does. 250+ shows on my last dance heavy show and 100+ on my
current and not a single pack lost due to moisture - I got tired of my
LCD screens dying because they got sweat trapped inside in a condom.
As for the mic, I
strain relief the
connector with a hellermann sleeve, doubling it over once with a loose sleeve, if it pops out I know the dancing is too extreme and I need to take a good look at
strain relief and mic placement. Sleeving too tight or too much can damage the mic. If you are using TA4F or locking 1/8", re-doing the
connector may help too. There are better options for TA4F than what
Shure ships, but re-doing the internal part of the connection with thicker
heat-shrink tubing and a more solid solder job can help make sure they don't rip out of the
connector.
When the mic comes off the actor, I either hang it in open air on hooks, or I put it in a tiny open bag facing upwards with a packet of silica
gel on the bottom, hoping the moisture wicks out. I leave the mic packs in shoe-bags, with a packet of silica
gel at the bottom of each slot. If a mic is sweated out and doesn't sound too good after it dries up, I take an eye dropped of distilled water, and a tiny fresh paint brush, and I
drop the distilled water right on the capsule, use the brush to move it around, and I let it air dry.
That being said, even on the best most dancing heavy show, lav mics are still perishable items, and despite your best efforts, you still will lose a few mics a week to vigorous stress. I budget anywhere from a lav a show to a lav a week depending on how intense the dancing/sweat is - whether it be sweat in the capsule, or a shorted
connector due to stress you just won't be able to win the battle 100% of the time.