Dear Uncle Dysfunctional,

It's our one-month anniversary and I'm taking my girlfriend to Paris for the weekend. I want to give her some nice underwear for the occasion. I don't know where to start. Help.

Tom, Putney

Jesus. She's already wearing your bollocks as earrings. No man in the history of shagging has ever remembered or acknowledged a one-month anniversary. Look, Tom, these are the rules for lingerie: Don't. Simple as. Your job is getting it off, not adding to it. That's all you've got to remember.

Never, ever give underwear. You don't know her size. Her friends will lie about her size. She'll lie about her size. Take an old bra into Agent Provocateur and the shop assistant will lie about her size.

Just going, "Oh, about a handful", isn't enough. Men and women see completely different things when they look at bras and knickers. No woman who doesn't keep tenners in her garter belt has ever worn red underwear. Men put on their Berlusconi heads when they step through the door of Victoria's Secret.

Women grow instantly frigid when presented with a bra and thong set. What they see is a whole night of humiliation and logistical and ergonomic problems. Any man who could choose aesthetic, sensual underwear in the correct size is not the sort of man they'd want to wear it for.

Here's what you need to know about erotic presents and Paris: give her a riding crop. Unless she's got a horse. If she's already got a horse it's not an erotic present, it's a cheap gift.