Deki no Ii Kiss, Warui Kiss

Meet Tetsuo Atarashi. Age: 32. Occupation: porn comic writer. Marital Status: single, but has an estranged 14-year-old son who he fathered at the irresponsible age of 17. Sexual Potency: Currently None. Given such circumstances, it seems only natural that all Tetsuo desires is a kiss potent enough to get him back to his A-Game. Unfortunately, life plays a cruel hand when his long-estranged and "gay" son, Haruka, suddenly shows up at his door! Thrust into fatherhood in a homoerotic world, what is Tetsuo to do?! Kiss All the Boys takes slap-stick comedy and raging hormones to the opposite extreme! (Source: Amazon)
Volume 3 contains the oneshot:
Summertime Accomplices