If both the plug and socket are correctly made, it's physically impossible - by the time the contacts on the plug are exposed, they've disconnected from the contacts in the socket. No matter how much you prod and poke, you should only ever come into contact with an insulated sleeve or a non-energised contact. Unfortunately there are a lot of non-compliant plugs being sold by disreputable online retailers.
It is possible to get a very mild shock from the plug contacts if the input capacitors of the appliance haven't fully discharged. This shouldn't happen with properly-designed appliances, but it's very unlikely to be dangerous if it does happen.
It is possible to get a very mild shock from the plug contacts if the input capacitors of the appliance haven't fully discharged. This shouldn't happen with properly-designed appliances, but it's very unlikely to be dangerous if it does happen.