Responses
http://www.mangago.zone/read-manga/toshigoro_no_otokonoko_to_are/
http://www.mangago.zone/read-manga/momoiro_junjou_danshi/
the ones that are more into experimenting are mostly shota:
http://www.mangago.zone/read-manga/child_epicurean/an/manga/child_epicurean/v01/c002/pg-8/
http://www.mangago.zone/read-manga/mimi_paradise/an/mimi-paradise-chapter-6.html/2/
http://www.mangago.zone/read-manga/kohitsuji_hokaku_keikaku/ (both ukes experimented with each other in the beginning)
Is there any yaoi manga with friends experimenting? It's okay if one likes another, but I am thinking of just boys being curious and experimenting.