Sensual Widow: The Squirming Tip of the Tongue (1997)

Ichiro was apparently a big shot during the bubble economy, but now he's the owner of a small, unassuming ramen stall. One day, a regular customer, Makoto, comes crying to him, saying he urgently needs a family so he can introduce his girlfriend to her widowed stepmother. Ichiro decides to quickly become a rental family and lend a hand...