A tactical wank is one where you manage to slip away in an awkward or boring situation to
masturbate in a
quick time frame and manage to get back without anyone noticing that you had gone away. Further more people must not have
knowledge of what has just taken place. A more informal slang term for this is "tac wank"
Example 1.
*R slips back hoping no one has notices his absence*
"Dude, we know that look, you have just been for a tactical wank haven't you."
Example 2.
"Where have you been son, we were having an
important dinner discussion about poor
university grades?"
*cough* No where, I just needed a minute."