Marriage is when your Tamagotchi marries and mates with another Tamagotchi, creating the next generation. There are several ways to do this. Only adult Tamagotchis that have reached the age of 5 can marry/mate. After 24 hours, your Tamagotchi will leave the next midnight and you will be left to care for the baby, the next generation.
At 12:30pm and 4:30pm, the band manager(Guitartchi) will bring another Tamagotchi to you. The Tamagotchi's will talk, and then a box that says 'Marry?' will pop up. If you select 'Yes', the Tamagotchis will be shown kissing, falling in love and getting married. An egg will appear and hatch a minute later. The Tama you married will live with your Tamagotchi.
If you practice often with your band, one of your band members will visit at 8:00pm and ask your Tamagotchi to marry them. Once again, if you choose 'Yes', the Tamagotchis will marry and a egg will be shown, which will hatch a minute later. The band member will live with your Tamagotchi.
If you connect a Familitchi and Music Star until they both reach their highest friendship levels, you can select 'Marry' and 'Give' on the Familitchi, and then select a Tamagotchi to send to your Music Star. The Familitchi character will appear as Nazotchi and will live with your Music Star Tamagotchi.
As with the Familitchi, you must connect the two Tamagotchis until they both reach their highest friendship levels. Eventually, the two will marry. Unlike the other methods of marriage, the Tamas will not live together. Each Tamagotchi will recieve an egg. The babies will be the same gender.