turn

You cannot perform a Flip Summon during your opponent's turn. A Flip Summon is a way of manually changing the monster's Battle Position. Since it is "manual", it can only be done during your own Main Phase. You cannot use Ultimate Offering to Flip Summon a monster during your opponent's turn...

Let's start with: you cannot Tribute a monster for no reason - say, if all your Monster Card Zones are occupied. You cannot Tribute a monster for a Tribute Summon the turn it is Summoned, because this would violate the "1 Normal Summon or Set per turn" rule. If you have Ultimate Offering active...

The general rule is that you can only "Normal Summon or Set 1 monster per turn". Usually when people "play a monster", this is what they mean. Tribute Summons count as Normal Summons, so you cannot Normal Summon a monster and Tribute Summon in the same turn. Special Summons can be done as often...