Being a fat bloke myself I can tell you exactly what is happening to your bike.
Your suspension is budget and not designed for your weight, when you sit on the bike you will use up all the sag.
As soon as you brake all the weight will go to the front and the arse end will go light and wander around. (the poor rear suspension doesn't help here.)
If you can't afford to have the suspension rebuilt to suit your weight, at least get springs rated to suit you and take advice on oil weight and amount.
I always have my bike suspension rebuilt and set up for me, K Tech front and rear on my Gen 1 1000, serviced every 3 or 4 years by MCT.
You could also try applying the rear brake a bit first, the bike should then stay a bit flatter when braking hard.
Your suspension is budget and not designed for your weight, when you sit on the bike you will use up all the sag.
As soon as you brake all the weight will go to the front and the arse end will go light and wander around. (the poor rear suspension doesn't help here.)
If you can't afford to have the suspension rebuilt to suit your weight, at least get springs rated to suit you and take advice on oil weight and amount.
I always have my bike suspension rebuilt and set up for me, K Tech front and rear on my Gen 1 1000, serviced every 3 or 4 years by MCT.
You could also try applying the rear brake a bit first, the bike should then stay a bit flatter when braking hard.