How to plot more than one locations (longitude + latitude) on google map?

I have an application which requires plotting two locations on google map ? One of these location will be my current location and second location is my friend's location which I have obtained.Now my problem is I'm abled to plot my friend's location on map but not abled to plot my location on same map.Can anyone tell me how to plot my location and my friend's location on same map ?I have an application which requires plotting t