Momi-chan
I don't know if it counts as a Yaoi song, but Orenji no Taiyou by Gackt and Hyde. It was the song their two characters- Sho and Kei- sang at the end of Moon Child.
There's also this song that Antony Rapp sings called Just Some Guy, and it's basically him singing about how sweetly his boyfriend treats him. It's so sweet and lovable.
OMG YES! <----Is a Gakuhai shipper. I didnt mention that one in my last post (hadn't seen Moon Child yet
gonk ) But YES. Its about them being in love and dying on the beach in each others arms by burning in the sunlight. Then of course there is Placebo (in perticular, 20th Centuary Boy [I wanna be your toy/boy
heart ]) Malchik Gay is a yes, or anything by Tatu. And MYV, oddly enough. I don't know why, but I love listening to Miyavi's Senor, Senora, Senorita when writing fanfiction.