Ancient people like to write with bamboo slips. . Ancient poets like to enjoy flowers and go for an outing.
So I think the author means a kind of love for the author.
It expresses that when writing poems, bamboo is used to promote taboo and salvation, but only when drinking with a bosom friend, flowers bloom is no longer just a time point, but also a date. For example, the poem "I'll come back when the chrysanthemum is on the mountain holiday" shows the poet's expectation for the flowers to bloom and his yearning for his friends.