Male bonding is pretty much the same as females though obviously don’t bond any more than two together and once bonded, make sure their final cage is big enough. Male trios etc are a lot less likely to work out then a pair.
You still should do it in a neutral area, offer veg/hay so they can graze together and still expect to see the mounting, rumblestrutting etc. Males might seem a bit more stand offish than sows but do not be deterred! The same still applies, sit it out unless blood is drawn or you fear a fight might escalate.
with boars I like to say try bonding two piggies who have two different characters I.e a shy pig with a more bold one. An older With a young etc