Three blokes with a speech impediment go to see the therapist.
Well blow me down she is the most stunning blonde nurse they have ever seen....
She says to the first guy " If you can tell me where you come from WITHOUT stuttering you get a first class blowjob"

So the first guy goes "M M MMM Manchester" and leaves all dejected.

The second guy goes " BB B B Birmingham" and leaves all dejected.

The third guy goes "London....." So quick as a flash she whips his old fella out and fulfils her red hot promise...

Just as he has finished he says "......derry."