Order them yourself and give her the keys
Asking for thighbands
If you need them to increase security at night then go for it. Another option is to agree some simple consequences for belt fighting.
thigh bands for men are useless in my opinion because they don't actually prevent anything. but if you want i can join Laura, order the thigh bands and ask her to hold the keys.
Do you have advices for ordering those thighbands? I dont know that accessory.
Verrouille basically for night (it's in bed that I struggle with my belt)
Then she would have to unlock them every morning.
It is unusual for men(and not sure it is useful),but it would be better than handcuffs...
Renita and also much more protective against male self-touch!
Renita stupid
So you know what is stupid or not?
i think i have to agree with @Renita on this one. how exactly would the increased security provided by thigh bands work for men? i don't get it
Verrouille Do you have advices for that request?
Being a man, you probably need to place the bands higher and the chain must be longer than for a girl. And since you wear a girlish chastity belt already, nothing wrong with thighbands. I think your gf will accept it.
hmmm.... I honestly think handcuffs are mlre usefull. That way your gf can make sure you don't tough yourself when she cleans your belt.
Angelina My girlfriend hates me to struggle with my belt. And when I struggle I spread the legs. That's the explanation.
- Edited
I think cuffs would be too restrictive overnight and without padding they'd tear up the wrists. I think @Tobbe once mentioned locking mittens (in the context of female chastity of course), but they'd make a lot more sense here than cuffs. You can get medical ones that force a flat palm, they were apparently used in the prison system long ago for a very similar purpose.
However, @Renita is correct that they'd have to be unlocked each morning, but if the gf really does hate belt-fighting she might put up with the (minor) inconvenience. Maybe they'd be kept, like @HHelen's bra idea, in reserve to be used if and when they're needed?
I can certainly see how they'd be useful in the example you gave, but I don't know how @Verrouille and his partner handle cleaning periods.
Verrouille So you know what is stupid or not?
Not all, but thighbands for men for sure.
maybe you should find something to reduce your struggling, then you wouldn't have to spread your legs. 
Jonas mentioned locking mittens
at least it sounds like a sensible idea. i don't think it's good, but it serves the purpose.
Renita So you know what is beeing a man better than a man despite you are not a man, quite interesting.
Jonas I think cuffs would be too restrictive overnight
Sure, it's nothing for over the night, just for the cleaning process. It could also cut the skin when trying to wear it overnight.
Tighbands?
holders might fear that the chaste person might be able to slide a finer under the shield, or any thin pencil or something like that. If you hold a vibrator to the stiff pencil then ...
But for men this obviously doesn't work - sure - to prevent him spreading the legs it would be useful ... that's bondage/restriction then. Therefore they are very useful. If she doesn't like your fighting she might also just hogtie you...