Catheter use!

Idk if this would help but ....
http://www.mangago.zone/tag/urethra%20play/

Ahh thanks

http://www.mangago.zone/read-manga/gintama_dj_where_is_your_switch/

http://www.mangago.zone/read-manga/pick_up/sa/sa-c001/15/
Enjoy~

These are my fav urethral play mangas :3
http://www.mangago.zone/read-manga/hajimari_wa_naka_kara/
http://www.mangago.zone/read-manga/haretara_kimi_o_mukae_ni_iku/
http://www.mangago.zone/read-manga/namida_hanamizu_gusyogusyo_danshi/ (Last chp)