It means "don't waste our time." However, I would highly recommend against using this expression. "Jerk off" also means "to masturbate" (for men), so if used in the wrong context, you might accidentally refer to a sexual act better performed in the privacy of one's home.

Never use this expression. "jerk off" means masturbate, which is where this expression gets its meaning from. Honestly, I haven't heard this phrase used many times at all. You would say it if you think what someone is saying to you is a lie told just to make you happy and you want them to stop lying and tell you the truth.