this probably counts as being pedantic, but one of the main purposes of this site is clarification and demystification. sooo...
when the OP said:
He then decided to screw around with me and D Doss me or however it's spelled
this particular spelling suggests that the first (or possibly only) time that the OP heard the term, it was spoken out loud. i.e. "dude i'm going to 'dee doss' the crap out of you". MOST professionals just use the letter acronym not the phonetic pronounciation ("dude, what's with the lag on my mail server? crap we're getting 'Dee Dee Oh Ess-ed'"). also the probability of some dingleberry down the street having a botnet under their own control for the sole purposes of being a dingleberry when they get fragged in a game is EXTREMELY low. that actually takes time and effort to set up. the only people who do DDoS attacks are people who have the time/desire to infect thousands of computers to DDoS a single MASSIVE target. it's also completely unnecessary to DDoS a single home computer, the probability of the OP having anything higher than a 16Mbps internet connection is low (though it's getting higher), it doesn't take a cloud of remotely controlled computers to clog a pipe that small to a point where playing a game is difficult or completely useless. especially a graphically intensive game.
i would postulate a guess that no single home user have ever been a victim of an actual DDoS. sure you might have 2 or 3 doofuses from 4chan hitting you at the same time, but that's not the same thing.
a DDoS is not a trivial event, it takes planning and coordination and a severe drive to pull it off. it's always targeted at a large entity like a company or government.
If you think your "friends" (as previously mentioned, it is a strange definition:)) should not get tired as a VPN connection to be a solution? When you receive the VPN's IP number and all data traffic passing through VPN tunnel before it comes out on the internet. Description of VPN: http://en.wikipedia.org/wiki/Vpn
to clarify this. a VPN is an encapsulation technique that's used to encapsulate and encrypt traffic between two network segments/endpoints through the public internet. a VPN allows you to create a private "tunnel" through the public internet to keep your traffic safe from casual inspection or interception. a VPN tunnel is just like a tunnel on a road through a mountain. it's got a defined starting point and a defined ending point. you can't have a tunnel with a variable endpoint. i.e. you drive in to the tunnel in france on your way to england, half way through you decide you'd much rather go to spain. the end of the tunnel isn't going to magically move to spain because you want it to.
it's the same with a VPN, you have to have two endpoints. a client (your computer or some other VPN capable network device) and a "server" (either an actual server, a computer or some other VPN capable network device).
a VPNs purpose is to encrypt and protect your traffic from prying eyes, it will not protect you from a DoS or a DDoS. if someone gets the public IP of either endpoint, they can simply fire their attack at that endpoint and bring the whole tunnel down.