The Valentine mod causes the affected player's skin to turn pink for 1 hour. At the same time hearts while fly from the affected player to the player who used the consumable as long as they remain in the same world.
If a player is in the same world as the player who got affected by the Valentine mod, it will say:
>> (affected player's name) is now (player who used the consumable's name)'s valentine!
When a player is affected by the Valentine mod the following text will show:
You are somebody's valentine! (Valentine mod added, 1 hour left)
When a player is no longer affected by the Valentine mod the following text will show:
Yuck! (Valentine mod removed)
Only the Valentine grants the Valentine mod.