BUR #23359 has been rejected.
create implication kneepit_sex -> frottage
create implication armpit_sex -> frottage
If not, the frottage wiki should be updated to exclude them in the definition.
I'd include thigh_sex too but it commonly involves genital contact, in which case it might not count as frottage anymore. That might need to be disambiguated in the wiki as well just in case.