slapsies

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun UK A game played by schoolchildren in which a group position themselves in a circle and each place one hand in the centre (normally on top of a table or other item of furniture). An ordinal number or another word such as "last" or "penultimate" is then called out by someone and whoever draws their hand away from the circle at that position has their hand slapped by the other players.