That all sounds good, but what about if the Vampire accidentally tackles you into the residence? He wouldn't be invited and he wouldn't have been forced in by someone else.

@bubbajake00 it wouldn’t be able to do that - it can’t willingly take action that breaks the forbiddance

If your house is open and it's located at the end of a staircase that goes down, what happens if the vampire stumbles over them? Or if you're walking on the roof and it breaks?

I’ve always imagined that the “effect” that makes vampires unable to enter a residence uninvited behaves like an invisible barrier or “force field”.

@JasonFiler that’s a totally sensible way to play it too

What happens if a house on sale was bought while a vampire was in it? Does it politely "push him out"? Or one cannot enter any house at all without a permission (even if it is noone's residence atm)? If part of PCs party manages to lure vampire into said house while other part is buying it, does it count as "forcing a Vampire indoors"(as in "other people's residence")?

@AntiDrondert Forbiddance specifically states the vampire "... can't enter a residence...." There is nothing about him being removed if he is otherwise already inside a residence without an invitation, nor any mental compulsion to leave.

@AntiDrondert "Being Human" did something like that on their show and killed all the rival vampires in one shot... was pretty sneaky... of course without specific verbiage the DM would make that decision.

I'm going with this as the answer because I agree that you can be invited in nonverbally, whether it is the wave of a hand or being dragged inside. Some would could even interpret a welcome mat in some instance (that's getting pretty lenient, though I can imagine funny situations where the vampire learns it doesn't count and is immediately expelled from the house).

"can force a vampire inside. This is allowed because it is not the vampire that is doing it." I smell a loophole coming up with multiple vampires walking up to a residence and part of the group forcing the other part of the group in. By agreement and on purpose. Surely it can't be that easy to circumvent?

@Mast That's what I was thinking as well. Just have one of their renfields push them in. Easy-peasy if this is allowed.

@Malkev That seems like a fun little test of the Vampirical Inquisition. Push them down stairs into homes, and, upon failure, get your stakes ready!

I think "the vampire can't" is ambiguous. One might interpret "can't" as "cannot by its own volition" as this answer does. Or one might interpret is meaning "physically cannot", which seems equally plausible (and less loophole-prone). In that case, perhaps trying to forcibly shove a vampire into a residence (by anyone other than a valid occupant) causes the vampire to teleport to the far side of the building. Ditto for accidentally crashing through a skylight. Build (or sell) a residence around a vampire, and they just appear outside of it the moment it's a complete residence, etc..

@Mast I would take the view that the vampire cannot enter the house in any fashion, and that the magic/curse prevents it from doing so by preventing any situation that would lead to the vampire entering uninvited; a physical invitation can let the vampire in, but being pushed in by someone with no right to invite will not work.

Similarly @Malkev, the vampire will not trip because it cannot enter the residence, simple as that.

This leads to an interesting case where vampires can identify burglars/squatters/etc by finding themselves unable to enter a residence after being invited in by that unwelcome occupant who lacks the 'right of invitation'.