Allegorical Wank

Cracking one out over an image which serves as a proxy for an intended (but unattainable) object of desire.

See also 'substitute shuftie' and 'simulacral shuffle'.

Baron Von Trapp couldn't make use of the new governess upon her arrival and so popped to the local church confessional booth with an image of the Virgin Mary for an allegorical wank.