Possible Clues:

• Thick-skinned enough so to summon you and me
• Give us a ring? That's a bit thick!
• Patch of hard skin
• Thickened skin patch
• Hard, thick skin area
• It's a bit thick to phone us like this
• It's a bit thick to give is a ring like this
• It's a bit thick to give us a ring like this
• It's 19 down and skinny for one to ring us up like this
• A sore point? Give us a ring