Change position of contourf labels

Hello

I need to produce a very neat contour plot to use for my journal paper. I have a filled contour of the pressures over a surface (I used contourf). Basically, I had vectors x and y which were locations on the surface and on each location, I had a value for pressure. I have a rectangular plot.

I would like to manually label the contour on just some lines. But when I use clabel(c,h,'manual'), after choosing the location by mouse, the number is rotated with no manner and is put in the middle of nowhere. I would like to choose the lines (in between different colors) and have the label in the middle of the line. Is there any way to do this?

In advance, I appreciate your help.

Thanks.