Meetings in revolutionary health resort involving pressure and lotion (12)

'meetings' is the definition.
(appointment is a kind of meeting)

'revolutionary health resort involving pressure and lotion' is the wordplay.
'revolutionary health resort' becomes 'aps' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'involving' indicates putting letters inside.
'pressure' becomes 'p' (abbreviation).
'and' says to put letters next to each other.
'lotion' becomes 'ointment' (I've seen this before).
'p'+'ointment'='pointment'
'aps' going around 'pointment' is 'APPOINTMENTS'.

'in' is the link.

Can you help me to learn more?