Ouch. We do a panel with 5-6 school administrators every year and I have been giving them lav mics attached to ties, shirt collars, dress collars, what have you, but they constantly turn their heads and brush their beards and clothing on them while talking. it was killing me and the student who is assigned to run sound for these presentations. Finally, I just bought cheapish headset mics and slipped them on over their ears. Some of them were slightly embarrassed to wear such an obvious mic, commenting on how they looked like they were Madonna in a concert, but the boom could be adjusted in the perfect place and they could all be heard perfectly.
Now I use them for our TEDX student shows and they have been perfect.
These are the ones I use:
https://www.amazon.com/gp/product/B009YAR24E/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
Surprisingly good sound if you are just doing a talking head.