VLAN hopping(switch spoofing)

Hi I am currently working on my final year project in school, I'm trying to do VLAN hopping specifically switch spoofing on my cisco 2950 switch.

After I configured VLAN 10 and 20 on my switch, I use KALI LINUX on my laptop to connect to fa0/1, I can ping to my other laptop at fa0/2 on 192.168.3.0/24 network, then I do yersinia- G on my KALI to send DTP packets to enable trunking, after I successfully make fa0/1 trunking port I try to ping my laptop on fa0/2 but it failed, I try to change my ip to be on 192.168.4.0 /24 network to ping to my other laptop on fa0/3 VLAN 20 but it failed too, I don't understand why, I did exactly what it states here but it doesn't work please help!!! https://www.exploit-db.com/docs/english/45050-vlan-hopping-attack.pdf

switch configuration:

int fa0/1

switchport mode dynamic auto

switchport access vlan 10

int fa0/2

switchport mode access

switchport access vlan 10

int fa0/3

switchport mode access

switchport access vlan 20