Add me to your calendar with a
soft maybe.
Means that you make plans to chizillax wit me but that shiz aint fo sho.
Implies flexibility of plans.
This comes from a
time when calendars were a written thing - you could schedule it in pen meaning you cant change it, cast it in
stone meaning 100% its on, or be wishy washy and pencil it in so you could erase and change it if need be.
can be used as n expression of flexibility:
Tom: Want to smoke a
blunt with me Saturday night?
Dick: I’ll be home after work
Tom: pencil me in for seven.
Dick FO SHO, U gonna SMD?
Tom: Nah