Cold fingers - put them around your neck.
- The neck exhibits excellent blood flow and thus, heating power
- The neck is easily accessible area of the body, unlike armpits, thighs, stomach (with all the layers of clothing)
- At least for me, it is not very stressful to press very cold fingers against the neck, compared to against e.g. stomach.
As for cold toes - I would probably try running, if excess energy is available. Wiggling the toes inside the shoe also helps. Furthermore it provides the added benefit of self-diagnosis - if you can't feel your toes or can't wiggle them, something is seriously wrong. Resort to emergency measures or you might lose them.