I'm Coming, Coming! summary:

Suho, an all-round part-timer, was willing to do anything for money. He was startled and ran away after accidentally witnessing his college sunbae Kanghyuk engaged in an S&M play at a motel during a routine pizza delivery.Kanghyuk later visits the stunned Suho and makes an offer for a part-time role as his acting lover, which Suho finds impossible to refuse...“Suho-ya, the boyfriend part-time job I asked of you also includes 'that kind of thing'.”