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Why their blood coming from the uke ass !!!!
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Probably tearing in his rectum, plus Leukemia and even the chemo affect blood cells. His platelet count is probably not great due to that since your bone marrow is responsible for their production. While Leukemia is the cancer of the bone marrow and blood. When your platelets are too low your blood cannot clot efficiently. Hence the tearing probably bled more than it would have if he had a healthy platelet count. Thrombocytopenia.
I have the non-cancerous opposite blood disorder, where my bone marrow overproduce platelets to an extreme amount. Before my diagnosis the first thing they had to rule out was cancer. Essential thrombocythemia
What the name of the manga in the second picture??? Please please please please please please please please please ☹☹☹☹
http://www.mangago.zone/read-manga/19_sai_no_porno_endeavor/
Thank you