You will be needing:
1. Probably a High-Rates Interlude server;
2. First account with a lv78 Paladin;
3. Second account with the charater you wish to add limitless "Touch of Life" Buff (for example: SpH lv70);
4. A PC that is able to run two Lineage]['s at one time.
Let me begin.
STEP 1: Login with the lv78 Paladin and go to any NPC that can change sub classes (ex.: Orc Guild in Giran).
STEP 2: Login with the second account that has the character which you want to add Touch of Life to. (ex.: lv70 SpH..).
STEP 3: With the second character (lv70 SpH) go to the same spot, near the same NPC (Sub-class changer) that Lv78 Paladin is at (Giran Orc Guild).
STEP 4: Skip if you have a fast PC Make both of your Lineage]['s to WINDOWED MODE (ALT+ENTER). You can also minimize the graphics. Try to change the windows from one Lineage to the second. If it changes fast - you are done, if not, change the resolution to the minimum. We need this to be able to switch between the two characters fast enough, because the buff can expire.
STEP 5: When standing with the two characters next to each other, and near the sub changing NPC, BUFF the second character with "Touch of Life". (ex.: With the Lv78 Paladin, use "Touch of Life" buff on Lv70 SpH, while being near a Sub-Changing NPC).
STEP 6: QUICKLY change sub-class to any of your choice (ex.: Lv40 Destroyer) with the "Touch of Life" buffed character (ex.: Lv70 SpH).
STEP 7: When you changed to your desired sub-class(ex.: Lv40 Destroyer), re-change to your base class again (ex.: lv70 SpH).
Now, when you changed to your base class, you should see, that "Touch of Life" buff is on your buff bar and it will never expire.
Hope that helped anyone.