Boar dating would usually happen at a rescue, could we know your location to recommend something ?
Usually for a dominant boar, which is what you have, you'd look for a more submissive companion by looking at the other pigs temperament, a good choice for these dominant pigs is a younger baby friend, around 6-8 weeks old, this gets the older pig to take on a 'daddy' or 'uncle' pig role which most people find is the most successful type of bonding.
Only one boar will be tried with your pig at one time, anymore could cause alot of stress however if one doesn't work it's usually best to wait a day or so before trying again to bond him.
Bonding is simple really but can be quite nerve racking so it's good to do alot of research into it,
The best place to try bonding is either outside in a run or inside in a bath tub, it has to be done somewhere that doesn't smell like either guinea pig, or else the guinea pig who's scent is there will become protective and dominant of it's 'patch' as such. Also once the pig has a companion you'll need to really scrub down the cage and accessories so there is no scent left from the other pig.
When you try to bond you want piles of hay, and 'bonding food' such as vegetables and grass that they can share to keep them occupied, like a dinner date ! you also, if trying a baby with an older boar, need a smaller box that only the baby can fit into, as the bonding can be stressful on a young pig, having somewhere he can get away into is best. Also having other hidey houses but with two exits so that no pig can be cornered and trapped!
When i was looking at bonding my boy i found this website helpful,
http://www.susieandpigs.pwp.blueyonder.co.uk/home.htm
Hope that helps,