From the Main Menu go into Multiplayer and then choose "Play With Friends". The online for this game is likely to be a little dead, so your best bet is to boost it with a Friend. Therefore I recommend one of you creates a match.
Once created the host will automatically be requested to choose a character. Pick anyone you want and once you have done that use the
guide and invite your friend into the lobby.
Whilst waiting for your friend to arrive, you can change the settings by pressing the
button in the game. I recommend the following settings to be applied...Course - Seaside Hill - Whale Lagoon
Laps - 3
Private Slots - 7
AI Racers - Off
Power-Ups - On
Catch-Up - Off
When your friend arrives, press
to begin the race. Now you both need to decide who is going for the win. Once decided have the winning person go round the track and complete 3 Laps, whilst the other player sits around and lets your partner pass-by. When they have finished the race, a timer will begin for the person who is sitting around. Let it run out and then the winning player will get this achievement. Swap roles in the next race and rinse and repeat for the other player that needs this achievement.