well, i think you are refuring to the match maker....
the match maker will come and ask if your lonley, if so, say yes. then you will mate with another tama that the match maker has selected.....the you have an offspring to start the next genertation. Im now looking for pics of the procedure, i cant remember what site they are from....so, ill post it soon (if i find it!)! Also, if your sons have tamagotchis, then they can mate with their brother(s) tamagotchis!!!!