After "A" comes "P", as every bright and well-educated child will tell you. And they will also tell you that, in Graybo’s Lexicon of Luuuurrvve (a book that should be in every school’s library), P is for Passion.
Passion is one of those things that can be both good or bad. In the right context, it can mean intense emotional feelings of love, lust and desire. In the wrong context, it can mean nailing some bloke to a tree.
It is important that you ensure that you are in the right context. Whilst there may be instances when it might be desirable to nail a bloke to a tree, the feelings that might drive such an action would not generally be considered to be positive in the context of luuuurrvve.
For a positive outcome, it is generally preferable for passion to be reciprocated by each member of a luuuurrvving partnership. If you are new to such a partnership (for example, having just met someone in a dodgy bar, or recruited someone to your team at work on the basis that they’re good looking) then you need to ensure that there are feelings of passion being returned to you. If there are not, then your own passionate ardour may result in at least a slap, or, at worst, unrequited luuuurrvve (q.v.).
So, how does one go about testing for feelings of passion in someone that you have only just met? Well, naturally, we at the Graybo Institute for Researching Luuuurrvve (G.I.R.L. – such an unfortunate acronym) recommend the patented G.I.R.L. Passion Meter available by mail order, only £29.99 each plus p&p.

Where you insert the probe is entirely up to you and will depend on the level of familiarity that you have with the subject. The Institute will not be held responsible for any consequences that may arise from the use of the meter. Terms and conditions apply.