Guinea pig bonding is very similar to rabbit bonding, although often a bit easier. Maybe pigs are just a bit more relaxed about dating!!
We have found the best combination to be two females or a female and a neutered male. Boar to boar bonding is possible but our personal opinion is that the bond is likely to be a bit more unstable. Please note that if bonding a neutered boar you must wait 8 weeks after his op. Guinea pigs are very potent and can still get a sow pregnant for a couple of months after neutering!!