The verb 'to squeeze' means to manage to get into a narrow or restricted space or to obtain something from someone with an amount of effort or difficulty. To squeeze in something or squeeze in somebody means to manage to fit them in to your schedule or plans when you are short on time. You could say you will 'squeeze in an appointment for someone' if your schedule is quite full but you intend to make space for them anyway. You could squeeze someone in to a physical space where there is little room, for example, 'We didn't expect so many people to show up, but we managed to squeeze in 150 people into the conference room."

1. Larry knew that he wouldn't get the chance to go to the gym later, so he squeezed in a workout during his lunch break.
2. I didn't think that the doctor would have any appointments left for tomorrow, but she is very kindly squeezing me in at 5.

1. Looking through my schedule, I will be busy all week, but I could squeeze you in for a quick meeting at 11.20 on Thursday morning if that suits? 
2. While you are in Beijing I strongly recommend you squeeze in a meeting with Gu, you could learn a lot from him.