1st Base - Is Kissing, french, open mouth or just a peck. Also any above the belt touching is included in this base
2nd Base - Hands below the belt. Fingering for girls or hand jobs for the guys.
3rd Base - When mouths are used below the belt. Essentially going down on a guy or girl. also This base includes the sex toys.
4th Base or Home base/plate - Going "all the way," doing the deed, Slamming it, Fucking, Sex, intercourse, "doin it," getting friskey so on and so forth.
(some people use a 5th base or a 'grand slam' to refer to anal sex while other include it in the 4th base. its really up to the individuals wheter they want to include it)
no example needed the sexual bases spelled out for you in the deffinition like a fricken manual