pitch in (type 1)

(join people in doing a job)

This won't take long if we all pitch in.

Let's pitch in and get this room tidy.

butter up (type 2)

(be especially nice to someone so that they do what you want)

The children were always buttering up their mother, so that she would give them sweets.

Are you trying to butter me up? It won't work!

veg out (type 1)

(sit still and do nothing)

I'm so tired. I just want to veg out tonight.

We've vegged out all weekend. We need to get some exercise now!

gloss over (type 3)

(say as little as possible about something)

She glossed over the details of her divorce.

They glossed over how late they had stayed out.

brush up on (type 4)

(practise an old skill)

I want to go to Spain to brush up on my Spanish.

She needs to brush up on her maths a bit.