Pencil in phrasal verb informal
To write something in pencil in order to modify or delete it afterwards.
I'll pencil you in to work the patio.
To arrange or plan something for a tentative or temporary time or date.
Let's pencil in 3 May for the meeting. We may always change the date if there are any problems with it.
To make a tentative appointment with someone.
You can pencil me in for lunch on Friday.
None
To deal with something when it happens without planning for it beforehand
What's planned for today?
Used to refer to an impossible plan or idea
A religious holiday that is on a different date each year.
To consider or think about what will happen in the future
The verb "pencil" should be conjugated according to its tense.
This usage, from the late 1900s, endures even though it may relate to blogging on an electronic device such as an iPad rather than writing in a journal. It's starting to seem cliched.
Used to allude that the last force, problem or burden which is seemingly minor and small causes a person, system or organisation to collapse or fail
Her husband's violent act last night was the straw that broke the donkey's back and she left him