WHAT’S THE AMOUNT OF INTERACTION NEEDED TO USE A SPELLCASTING FOCUS? DOES IT HAVE TO BE INCLUDED IN THE SOMATIC COMPONENT?
If a spell has a material component, you need to handle that component when you cast the spell (see page 203 in the Player’s Handbook). The same rule applies if you’re using a spellcasting focus as the material component.
If a spell has a somatic component, you can use the hand that performs the somatic component to also handle the material component. For example, a wizard who uses an orb as a spellcasting focus could hold a quarterstaff in one hand and the orb in the other, and he could cast lightning bolt by using the orb as the spell’s material component and the orb hand to perform the spell’s somatic component.
Another example: a cleric’s holy symbol is emblazoned on her shield. She likes to wade into melee combat with a mace in one hand and a shield in the other. She uses the holy symbol as her spellcasting focus, so she needs to have the shield in hand when she casts a cleric spell that has a material component. If the spell, such as aid, also has a somatic component, she can perform that component with the shield hand and keep holding the mace in the other.
If the same cleric casts cure wounds, she needs to put the mace or the shield away, because that spell doesn’t have a material component but does have a somatic component. She’s going to need a free hand to make the spell’s gestures. If she had the War Caster feat, she could ignore this restriction.
https://dnd.wizards.com/articles/sage-advice/rules-spellcasting
WHAT’S THE AMOUNT OF INTERACTION NEEDED TO USE A SPELLCASTING FOCUS? DOES IT HAVE TO BE INCLUDED IN THE SOMATIC COMPONENT?
If a spell has a material component, you need to handle that component when you cast the spell (see page 203 in the Player’s Handbook). The same rule applies if you’re using a spellcasting focus as the material component.
If a spell has a somatic component, you can use the hand that performs the somatic component to also handle the material component. For example, a wizard who uses an orb as a spellcasting focus could hold a quarterstaff in one hand and the orb in the other, and he could cast lightning bolt by using the orb as the spell’s material component and the orb hand to perform the spell’s somatic component.
Another example: a cleric’s holy symbol is emblazoned on her shield. She likes to wade into melee combat with a mace in one hand and a shield in the other. She uses the holy symbol as her spellcasting focus, so she needs to have the shield in hand when she casts a cleric spell that has a material component. If the spell, such as aid, also has a somatic component, she can perform that component with the shield hand and keep holding the mace in the other.
If the same cleric casts cure wounds, she needs to put the mace or the shield away, because that spell doesn’t have a material component but does have a somatic component. She’s going to need a free hand to make the spell’s gestures. If she had the War Caster feat, she could ignore this restriction.
We are all aware of what Sage Advice says on the matter, wipeout409, but the fact remains that Sage Advice is not RAW.