How do I do the equivalent to 'git pull --rebase <remote> <branch>' ?

[Fred Ross-Perry]

When working in a branch, I want to update it from the trunk periodically.

So I'll pop out to a terminal window and do 'git pull --rebase' from the trunk.

How do I do that in SourceTree?

I should point out that my branch is NOT tracking the trunk branch. I usually create a branch, stick it on my private remote, and work there.