In height/ and or size
These aren't mine so some manga might be repeated
http://www.mangago.zone/home/mangalist/43665/
http://www.mangago.zone/tag/small!uke%2Fbig!seme/
http://www.mangago.zone/tag/tiny+uke/
http://www.mangago.zone/tag/Small+uke/
Sorry I accidentally disliked Σ(っ°Д °;)っ
http://www.mangago.zone/read-manga/lucky_number_13/
http://www.mangago.zone/read-manga/sentimental_garden_lover/
http://www.mangago.zone/read-manga/majouu_school_days/
http://www.mangago.zone/read-manga/amai_kimi_ga_suki/
http://www.mangago.zone/read-manga/love_me_baby_sasamura_gou/
http://www.mangago.zone/read-manga/ashita_wa_docchi_da/
http://www.mangago.zone/read-manga/mawaru_sekai_no_kimi_to_boku/
http://www.mangago.zone/read-manga/hidoi_otoko_aoi_akira/
http://www.mangago.zone/read-manga/ikujinashi_no_spectator/
http://www.mangago.zone/read-manga/pink_no_omocha/
http://www.mangago.zone/read-manga/kono_ore_ga_omae_nanka_suki_na_wakenai/
http://www.mangago.zone/read-manga/kachou_wa_kakko_ii/
http://www.mangago.zone/read-manga/ossu_ren_ai_gakuen/
http://www.mangago.zone/read-manga/high_school_lullaby/
http://www.mangago.zone/read-manga/usagi_otoko_tora_otoko/
http://www.mangago.zone/read-manga/ijiwaru_na_kuchizuke/
http://www.mangago.zone/read-manga/furueru_yoru_no_himitsugoto/
http://www.mangago.zone/read-manga/hitomi_no_dokusenyoku/
http://www.mangago.zone/read-manga/hatsujou_animal/
http://www.mangago.zone/read-manga/darling_ougi_yuzuha/
http://www.mangago.zone/read-manga/tomodachi_ijou_no_koto_shitai/
http://www.mangago.zone/read-manga/brothers_yamamoto_kotetsuko/
http://www.mangago.zone/read-manga/oujisama_ni_narenai/
http://www.mangago.zone/read-manga/nar_kiss/
http://www.mangago.zone/read-manga/kimi_no_karada_ni_koishiteru/
http://www.mangago.zone/read-manga/fukurou_kun_to_kare/
http://www.mangago.zone/read-manga/royal_fiance/
http://www.mangago.zone/read-manga/shouwaru_ookami_ga_koi_wo_shita_rashii/
The "smaller in weight and height not penis size" made me laugh out loud. LOL. ε=ε=(ノ≧∇≦)ノ
haha
my uke is tall x seme is short collection http://www.mangago.zone/home/mangalist/45879/
sorry i read it backwards. (sometimes my filter is...) haha. i have the tiny uke x tall hunky seme in a separate collection http://www.mangago.zone/people/tag/49344/height+gap/
a yaoi manga with a uke that smaller than the seme. (smaller in weight and height not penis size XD)